Name: a method to assess fc-mediated effector functions induced by influenza hemagglutinin specific antibodies
Uploaded: 2018-02-23T12:30:00
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이 프로젝트는 자금을 일부 알레르기 국립 연구소와 전염병에서 연방 자금, 건강의 국가 학회, 학과의 보건 및 인적 서비스, CEIRS 아래 계약 P01AI097092-04S1 (P.E.L.).

이 원고에서 preformed 실험 윤리 및 규정의 다음 아이 칸의 학부의 기관 코드를 완료 했다.
1. 인플루엔자 바이러스 조류 Transfection 또는 감염의 표현
Transfection:
<ol><li>플레이트 인간 미 발달 신장 (HEK 293T) 셀 셀/잘 백색 조직 문화에서에서 2 x 104 의 밀도에서 96 잘 접시를 처리 하 고 (와 함께 5% CO2) 37 °C 배양 기에서 4...

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여기에 설명 된 메서드를 사용 하면 murine FcγRIV 참여 하 특정 단일 클론 항 체의 능력을 측정 하 수 있습니다. 대상 항 인플루엔자 바이러스 조류 바이러스 또는 플라스 미드 DNA의 transfection 감염 후 세포의 표면에 표현 된다. 분석 결과 (인간 또는 murine) 다른 FcγRs와 함께에서 다른 표면 표현 바이러스 성 단백질을 사용 하 여 의무가 더 이다. 또한, 우리는 세라 샘플 사용 Fc effector 기능 (데이터 표시 ...

계절 독감 백신에서 제공 하는 면역은 전통적으로 hemagglutination 억제 (HI) 분석 결과1, 대상으로 하는 조류의 수용 체 바인딩 사이트 항 체의 존재를 측정 하 여 평가 되었습니다. 이러한이 활성 항 체 살 균 면역을 부여 수 있습니다 하지만 일반적으로 인플루엔자 바이러스의 단지 선택 몇 가지 계통에 면역을 제공 하는 보호의 그들의 범위에서 좁은. 격리 및 조류 (HA)를 인식 하는 광범위 하 게 반응 단일 클론 항 체의 특성화 제안 범용 인플루엔자 백신의 개발은 도달 시간2,,34, 5 , 6 , 7 , 8. 인플루엔자 바이러스9,10,,1112 의 보존된 지역으로 강한 항 체 응답을 유도 하는 것은 보편적인 인플루엔자 백신의 주요 목표 중 하나 , 13 , 14 , 15 , 16. 이러한 보존된 epitopes, 중화 및 비 중화 항 체17,18의 인식 반응 항 체 Fc-FcγR 상호 작용에 대 한 요구를 광범위 하 게 표시 되었습니다 최적의 vivo에서 보호 하 고 하이라이트 Fc 중재 면역 인플루엔자 바이러스19,20전반적인 면역 응답에의 기여.
보호의 관계가 중요 한 감염에 면역을 평가에 있습니다. 이러한 통계 과학자와 임상 백신의 효능, 데이터의 의미와 치료 과정을 추정 하실 수 있습니다. 인플루엔자 바이러스 감염에 대 한 보호의 유일한 설립된 상관 hemagglutination 저해 분석 결과 이다. 1시 40분의 titer 질병1,21 -위험 50% 감소와 관련 이며 바인딩 사이트는 HA의 구형 머리에 있는 수용 체를 대상으로 교착을 억제 하는 항 체의 존재를 반영 한다. 그러나, 그것은 또한 주목 해야한다 T 세포 응답 노인에서 인플루엔자 바이러스 감염에 대 한 보호의 더 나은 상관 있을 수 있습니다. 흥미롭게도, 최근 보고서 응집 저해 행위 면책 독감22의 더 나은 예언자를 있을 수 있습니다 제안 합니다. 다행히도, 일반적인 체 외에서 분석 실험 같은 중화 또는 응집 저해 분석 하 줄기 또는 응집 특정 항 체를 측정할 수 있습니다. 그러나 대부분 이러한 기존의 시험관에서 분석의,만 항 체의 항 원 바인딩 영역의 기능을 고려 하 고 Fc 영역의 역할을 측정 하지 않습니다. 또한, 비 중화 항 체 Fc 수용 체 참여에서 vivo에서 를 통해 보호 하는의 기여 감지17,18되지 않습니다. Fc 중재 면역 항 체 의존 세포 중재 세포 독성 (ADCC) 등을 유발 하는 항 체에 의해 여유 보호를 측정 하기 위하여 강력한 생체 외에서 시험이 필요 합니다.
아래 설명 하는 방법을 평가 수 murine 단일 클론 항 체의 Fc 중재 기능 활성화는 표현 유전자 변형된 Jurkat 세포 라인 사용 유도 murine 입력 1 FcR, FcγRIV. 항 체는 FcγR의 교전 세포내 신호 트리거 활성화 된 T 세포 중재 luciferase 활동의 핵 요인 transduces. 분석 결과 여러 장점이 격리 및 기본 효과 기 세포의 문화 및 cytometry Fc 중재 effector 기능19,23,24의 활성화를 감지를 사용 하 여 요구 하는 전통적인 기법 ,,2526. 첫째, 여기에 설명 된 프로토콜을 쉽게 통합 하는 다른 바이러스 성 대상, FcγRs, 및 다른 종 (인간과 murine)에서 항 체 적용할 수 있습니다. 둘째, 수정된 Jurkat 세포를 사용 하 여 표현 하는 활성화 된 T 세포 (NFAT)의 핵 요인 아래 luciferase 취재 원 유전자와 FcγR 발광 측정 플레이트 리더를 사용 하 여 쉽게 분석할 수 있는 대형 분석 결과 대 한 수 선. 여기, 기본 효과 기 세포의 전통적인 활성화 Jurkat 세포의 표면에 FcγR의 항 체 참여 시 NFAT luciferase의 유도로 대체 됩니다. 이 96 잘 접시 형식 분석 결과 7 희석-성가신 전통적인 기술을 사용 하 여 될 수 있는 샘플 수와 triplicates에서 최대 4 개의 서로 다른 샘플의 측정에 대 한 수 있습니다. 이 분석 결과 실험의 설계 및 데이터의 해석에 영향을 미칠 수 있습니다 고려해 야 할 추가 포인트가 있다. 바이러스 성 대상 항 체 인식에 세포 표면에 표현 해야 합니다. 이 줄이기 위해 대상 항 원 (예: 내부 바이러스 성 단백질)는 격판덮개의 표면에 직접 코팅 수 수 있습니다. 그러나, 이것은 아직 엄격 하 게 테스트 되지. 또한, 수정 된 Jurkat 세포 선 및 FcγR 활성화의 한 유형을 표현 1 차 셀 라인 표현 생리 적 맥락에서 모든 수용 체 어떤 금지 FcγRs을 표현 하지 않는다.
우리가 이전 polyclonal 컨텍스트에서 epitope 특이성 Fc 중재 effector 기능 조절에 중요 한 역할을 담당 하며 그 항 체-종속 셀 중재 응답의 최적 활성화의 두 가지 포인트를 설명 하기 위해이 분석 결과 사용 27,28문의. 여기, 우리가 참여 하 고 FcγRIV를 활성화 murine 활성화 줄기 특정 단일 클론 항 체의 능력을 평가 하는 방법을 설명 합니다. 예외29,30비록 광범위 하 게 반응 항 체의 많은 수는 조류의 antigenically 보존된 스토킹 지역 대상 고 따라서 범용 인플루엔자의 개발에 중요 한 역 백신입니다.

<table border="0" cellpadding="0" cellspacing="0" width="921">
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">A549 cells&#160;</td>
			<td style="width:141px;">ATCC</td>
			<td style="width:184px;">CCL-185</td>
			<td style="width:353px;">Adenocarcinomic human alveolar basal epithelial cells</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">HEK 293T cells</td>
			<td style="width:141px;">ATCC</td>
			<td style="width:184px;">CRL-3216</td>
			<td>Human embryonic kidney cells</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">Lipofectamine 2000</td>
			<td style="width:141px;">Life Technologies&#160;</td>
			<td style="width:184px;">11668019</td>
			<td>Transfection reagent</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">1X Opti-MEM Reduced Serum Medium</td>
			<td>ThermoFisher Scientific</td>
			<td style="width:184px;">51985-034</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">White tissue culture treated 96-well plate</td>
			<td>Corning, Inc.&#160;</td>
			<td>3917</td>
			<td>Assay plates</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">10X MEM</td>
			<td style="width:141px;">Gibco</td>
			<td style="width:184px;">11430-030</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:243px;">Jurkat cell expressing murine FcgRIV</td>
			<td style="width:141px;">Promega</td>
			<td style="width:184px;">M1201</td>
			<td>Kit provides includes cells, Bio-Glo Luciferase assay system, 1X RPMI and low IgG serum</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:243px;">Jurkat cell expressing human FcgRIIIa</td>
			<td style="width:141px;">Promega</td>
			<td style="width:184px;">G7010</td>
			<td>Kit provides includes cells, Bio-Glo Luciferase assay system, 1X RPMI and low IgG serum</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:243px;">Jurkat cell expressing human FcgRIIa</td>
			<td style="width:141px;">Promega</td>
			<td style="width:184px;">G9901</td>
			<td>Kit provides includes cells, Bio-Glo Luciferase assay system, 1X RPMI and low IgG serum</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Luminometer</td>
			<td>BioTek</td>
			<td>Synergy H1 Multi-Mode reader</td>
			<td>Luminescence plate reader</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">Bio-Glo Luciferase Assay System</td>
			<td style="width:141px;">Promega</td>
			<td style="width:184px;">G7940</td>
			<td>Contains luciferase assay buffer and luciferase assay substrate</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:243px;">Madin Darby canine kidney cells</td>
			<td style="width:141px;">ATCC</td>
			<td style="width:184px;">CCL-34</td>
			<td>Canine kidney cells</td>
		</tr>
	</tbody>
</table>

a method to assess fc-mediated effector functions induced by influenza hemagglutinin specific antibodies

항 체 항 원 바인딩 도메인 Fc 영역을 통해 바이러스 성 병원 체에 대 한 타고 난 및 적응형 면역 응답 커플링에 중요 한 역할을 한다. 여기, 우리가 활성화를 측정 하는 방법에 설명 Fc의 단일 클론 항 체는 활성화 표현 유전자 조작된 Jurkat 세포 라인의 사용으로 인플루엔자 바이러스 조류를 대상으로 하 여 이펙터 기능 입력 1 Fc-FcγR. 전송 시각:이 메서드를 사용 합니다 특정 Fc-FcγR 상호 작용 면역 글로불린에 의해 수 여의 생체 외에서 분석 결과 사용 하 여 확인할 수 있습니다.

우리는 시연 스토킹 전용 mAb, 6F12, 하지만 하지 머리 전용 머리 전용 mAb, PY102, upregulating CD107a 및 인터페론 γ19에 의해 기본 자연 킬러 세포를 활성화할 수 있었습니다. 모델링 기본 인간 NK 세포를 활성화 하는 스토킹 특정 항 체의 능력, 우리 스토킹 관련 mAb, 6F12, 튼튼하게 의해 murine FcγRIV 표현 수정된 Jurkat 세포를 활성화할 수 있습니다 보여 ~ 14-fold. 다른 한편으로, 머리 전용 mAb, P...

Watch this Scientific Journal Video about A Method to Assess Fc-mediated Effector Functions Induced by Influenza Hemagglutinin Specific Antibodies at JoVE.com

A Method to Assess Fc-mediated Effector Functions Induced by Influenza Hemagglutinin Specific Antibodies

항 체에 의해 그 대상 인플루엔자 바이러스 조류 Fc 중재 effector 기능 활성화를 측정 하는 방법을 설명 합니다. 이 분석 결과 또한 Fc 중재 면역 유도의 단일 클론 항 체 또는 polyclonal 세라 다른 바이러스 표면 glycoproteins를 대상으로 능력을 평가 하기 위해 적응 수 있습니다.

독감 조류 특정 항 체에 의해 유도 된 Fc 중재 Effector 기능을 평가 하는 방법

Antibodies play a crucial role in coupling the innate and adaptive immune responses against viral pathogens through their antigen binding domains and ...

The overall goal of this protocol is to assess the ability of an antibody or a serum sample to activate Fc-mediated effector function. This method can help answer key questions in the immunology and vaccinology fields by measuring the activation of antibody-dependent Fc-mediated immunity. The main advantage of this technique is that the experiment can be done within 24 hours from the material preparation to the data analysis.Demonstrating this procedure will be Mark Bailey, graduate student from the laboratory of Peter Palese. To induce influenza virus hemagglutinin expression via transfection, first plate human embryonic kidney 293 cells at a two times 10 to the fourth cells per well concentration in a white tissue culture treated 96-well plate. After four hours at 37 degrees Celsius and 5%CO2, transfect the cells with 100 nanograms of DNA coding for viral hemagglutinin and 0.2 microliters of transfection reagent per well and a total volume of 50 microliters of 1X optimum-reduced serum medium.Add DNA liposome complexes to each well to transfect and return the plate to the incubator for another 18 hours. To induce influenza virus hemagglutinin expression via infection, plate A549 cells at a two times 10 to the fourth cells per well concentration in a white tissue culture treated 96-well plate for an at least 18-hour incubation at 37 degrees Celsius and 5%CO2. At the end of the incubation, dilute the influenza virus to a multiplicity infection of three in 100 microliters of 1X MEM medium per well and infect the A459 cells for one hour in the cell culture incubator.At the end of the incubation, replace the inoculum with 100 microliters of fresh 1X MEM medium without virus and return the cells to the incubator for another 18 to 24 hours. To assess the ability of specific antibodies of interest to target the hemagglutinin-expressing cells, replace the supernatant of the virally-affected cell cultures with 25 microliters of Antibody-Dependent Cell-mediated Cytotoxicity or ADCC assay medium. Next, in a separate 96-well plate, perform four full dilutions of the antibodies of interest in triplicate in fresh ADCC medium starting at 10 micrograms per milliliter according to the schematic and taking care to include the background and no antibody controls.When all of the antibody has been diluted, transfer 25 microliters of the diluted antibody to the appropriate corresponding wells in the experimental cell plate and place the plate in the cell culture incubator. After 15 minutes, add 7.5 times 10 to the fourth modified effector Jurkat cells expressing the appropriate Fc receptor per well in 25 microliters of ADCC medium for a final volume of 75 microliters of ADCC medium per well. Return the plate to the cell culture incubator for six hours thawing luciferase substrate buffer in a 37 degree Celsius water bath during the last hour of the incubation.When the buffer is ready, add 75 microliters of luciferase substrate buffer to all of the wells except the background control well and read the plate on a luminometer. The fold induction of antibody-dependent cell-mediated cytotoxicity in the transfected or infected cell cultures can then be calculated. In this experiment, a stock-specific monoclonal antibody robustly activated and modified Jurkat cells expressing murine Fc gamma receptor four by approximately 14-fold compared to head-specific monoclonal and control IgG antibodies.After watching this video, you should have a good understanding of how to set up an experiment for assessing the ability of specific antibodies of interest to activate Fc-mediated immunity.

a-method-to-assess-fc-mediated-effector-functions-induced-influenza

Research

JoVE Journal

Immunology and Infection

Quantitative Analyses of all Influenza Type A Viral Hemagglutinins and Neuraminidases using Universal Antibodies in Simple Slot Blot Assays

Hemagglutinin (HA) and neuraminidase (NA) are two surface proteins of influenza viruses which are known to play important roles in the viral life cycle and the induction of protective immune responses1,2. As the main target for neutralizing antibodies, HA is currently used as the influenza vaccine potency marker and is measured by single radial immunodiffusion (SRID)3. However, the dependence of SRID on the availability of the corresponding subtype-specific antisera causes a minimum of 2-3 months delay for the release of every new vaccine. Moreover, despite evidence that NA also induces protective immunity4, the amount of NA in influenza vaccines is not yet standardized due to a lack of appropriate reagents or analytical method5. Thus, simple alternative methods capable of quantifying HA and NA antigens are desirable for rapid release and better quality control of influenza vaccines.
Universally conserved regions in all available influenza A HA and NA sequences were identified by bioinformatics analyses6-7. One sequence (designated as Uni-1) was identified in the only universally conserved epitope of HA, the fusion peptide6, while two conserved sequences were identified in neuraminidases, one close to the enzymatic active site (designated as HCA-2) and the other close to the N-terminus (designated as HCA-3)7. Peptides with these amino acid sequences were synthesized and used to immunize rabbits for the production of antibodies. The antibody against the Uni-1 epitope of HA was able to bind to 13 subtypes of influenza A HA (H1-H13) while the antibodies against the HCA-2 and HCA-3 regions of NA were capable of binding all 9 NA subtypes. All antibodies showed remarkable specificity against the viral sequences as evidenced by the observation that no cross-reactivity to allantoic proteins was detected. These universal antibodies were then used to develop slot blot assays to quantify HA and NA in influenza A vaccines without the need for specific antisera7,8. Vaccine samples were applied onto a PVDF membrane using a slot blot apparatus along with reference standards diluted to various concentrations. For the detection of HA, samples and standard were first diluted in Tris-buffered saline (TBS) containing 4M urea while for the measurement of NA they were diluted in TBS containing 0.01% Zwittergent as these conditions significantly improved the detection sensitivity. Following the detection of the HA and NA antigens by immunoblotting with their respective universal antibodies, signal intensities were quantified by densitometry. Amounts of HA and NA in the vaccines were then calculated using a standard curve established with the signal intensities of the various concentrations of the references used. 
Given that these antibodies bind to universal epitopes in HA or NA, interested investigators could use them as research tools in immunoassays other than the slot blot only.

A simple slot blot method was developed for the quantification of influenza viral hemagglutinin and neuraminidase using universal antibodies targeting their most conserved sequences identified through bioinformatics analyses. This innovative approach may provide a useful alternative to quantitative determination of all viral hemagglutinin and neuraminidase.

모든 독감의 양적 분석 간단한 슬롯 얼룩 Assays에서 유니버설 항체를 사용하는 바이러스성 Hemagglutinins 및 Neuraminidases를 입력하십시오

Hemagglutinin (HA) and neuraminidase (NA) are two surface proteins of influenza viruses which are known to play important roles in the viral life cycle ...

연구

면역학 및 감염병학

High-throughput Detection Method for Influenza Virus

Influenza virus is a respiratory pathogen that causes a high degree of morbidity and mortality every year in multiple parts of the world. Therefore, precise diagnosis of the infecting strain and rapid high-throughput screening of vast numbers of clinical samples is paramount to control the spread of pandemic infections. Current clinical diagnoses of influenza infections are based on serologic testing, polymerase chain reaction, direct specimen immunofluorescence and cell culture 1,2.
Here, we report the development of a novel diagnostic technique used to detect live influenza viruses. We used the mouse-adapted human A/PR/8/34 (PR8, H1N1) virus 3 to test the efficacy of this technique using MDCK cells 4. MDCK cells (104 or 5 x 103 per well) were cultured in 96- or 384-well plates, infected with PR8 and viral proteins were detected using anti-M2 followed by an IR dye-conjugated secondary antibody. M2 5 and hemagglutinin 1 are two major marker proteins used in many different diagnostic assays. Employing IR-dye-conjugated secondary antibodies minimized the autofluorescence associated with other fluorescent dyes. The use of anti-M2 antibody allowed us to use the antigen-specific fluorescence intensity as a direct metric of viral quantity. To enumerate the fluorescence intensity, we used the LI-COR Odyssey-based IR scanner. This system uses two channel laser-based IR detections to identify fluorophores and differentiate them from background noise. The first channel excites at 680 nm and emits at 700 nm to help quantify the background. The second channel detects fluorophores that excite at 780 nm and emit at 800 nm. Scanning of PR8-infected MDCK cells in the IR scanner indicated a viral titer-dependent bright fluorescence. A positive correlation of fluorescence intensity to virus titer starting from 102-105 PFU could be consistently observed. Minimal but detectable positivity consistently seen with 102-103 PFU PR8 viral titers demonstrated the high sensitivity of the near-IR dyes. The signal-to-noise ratio was determined by comparing the mock-infected or isotype antibody-treated MDCK cells.
Using the fluorescence intensities from 96- or 384-well plate formats, we constructed standard titration curves. In these calculations, the first variable is the viral titer while the second variable is the fluorescence intensity. Therefore, we used the exponential distribution to generate a curve-fit to determine the polynomial relationship between the viral titers and fluorescence intensities. Collectively, we conclude that IR dye-based protein detection system can help diagnose infecting viral strains and precisely enumerate the titer of the infecting pathogens.

This method describes the use of Infrared dye based imaging system for detection of H1N1 in bronchioalveolar lavage (BAL) fluid of infected mice at a high sensitivity. This methodology can be performed in a 96- or 384-well plate, requires &lt;10 &mu;l volume of test material and has the potential for concurrent screening of multiple pathogens.

인플루엔자 바이러스에 대한 높은 처리량 검출 방법

Influenza virus is a respiratory pathogen that causes a high degree of morbidity and mortality every year in multiple parts of the world. Therefore, ...

In Vitro Assay to Evaluate the Impact of Immunoregulatory Pathways on HIV-specific CD4 T Cell Effector Function

T cell exhaustion is a major factor in failed pathogen clearance during chronic viral infections. Immunoregulatory pathways, such as PD-1 and IL-10, are upregulated upon this ongoing antigen exposure and contribute to loss of proliferation, reduced cytolytic function, and impaired cytokine production by CD4 and CD8 T cells. In the murine model of LCMV infection, administration of blocking antibodies against these two pathways augmented T cell responses. However, there is currently no in vitro assay to measure the impact of such blockade on cytokine secretion in cells from human samples. Our protocol and experimental approach enable us to accurately and efficiently quantify the restoration of cytokine production by HIV-specific CD4 T cells from HIV infected subjects.
Here, we depict an in vitro experimental design that enables measurements of cytokine secretion by HIV-specific CD4 T cells and their impact on other cell subsets. CD8 T cells were depleted from whole blood and remaining PBMCs were isolated via Ficoll separation method. CD8-depleted PBMCs were then incubated with blocking antibodies against PD-L1 and/or IL-10R&#945; and, after stimulation with an HIV-1 Gag peptide pool, cells were incubated at 37 &#176;C, 5% CO2. After 48 hr, supernatant was collected for cytokine analysis by beads arrays and cell pellets were collected for either phenotypic analysis using flow cytometry or transcriptional analysis using qRT-PCR. For more detailed analysis, different cell populations were obtained by selective subset depletion from PBMCs or by sorting using flow cytometry before being assessed in the same assays. These methods provide a highly sensitive and specific approach to determine the modulation of cytokine production by antigen-specific T-helper cells and to determine functional interactions between different populations of immune cells.

In Vitro Assay to Evaluate the Impact of Immunoregulatory Pathways on HIV-specific CD4 T Cell Effector Function

We developed an in vitro assay to investigate the role of immunoregulatory pathways in the regulation of cytokine secretion by HIV-specific CD4 T cells.

시험 관내 분석에서 HIV 특정 CD4 T 세포의 이펙터 기능에 면역 경로의 영향을 평가하기

T cell exhaustion is a major factor in failed pathogen clearance during chronic viral infections. Immunoregulatory pathways, such as PD-1 and IL-10, are ...

In vitro Coculture Assay to Assess Pathogen Induced Neutrophil Trans-epithelial Migration

Mucosal surfaces serve as protective barriers against pathogenic organisms.&#160;Innate immune responses are activated upon sensing pathogen leading to the infiltration of tissues with migrating inflammatory cells, primarily neutrophils.&#160;This process has the potential to be destructive to tissues if excessive or held in an unresolved state.&#160; Cocultured in vitro models can be utilized to study the unique molecular mechanisms involved in pathogen induced neutrophil trans-epithelial migration.&#160;This type of model provides versatility in experimental design with opportunity for controlled manipulation of the pathogen, epithelial barrier, or neutrophil.&#160;Pathogenic infection of the apical surface of polarized epithelial monolayers grown on permeable transwell filters instigates physiologically relevant basolateral to apical trans-epithelial migration of neutrophils applied to the basolateral surface.&#160;The in vitro model described herein demonstrates the multiple steps necessary for demonstrating neutrophil migration across a polarized lung epithelial monolayer that has been infected with pathogenic P. aeruginosa (PAO1).&#160;Seeding and culturing of permeable transwells with human derived lung epithelial cells is described, along with isolation of neutrophils from whole human blood and culturing of PAO1 and nonpathogenic K12 E. coli (MC1000).&#160; The emigrational process and quantitative analysis of successfully migrated neutrophils that have been mobilized in response to pathogenic infection is shown with representative data, including positive and negative controls.&#160;This in vitro model system can be manipulated and applied to other mucosal surfaces.&#160;Inflammatory responses that involve excessive neutrophil infiltration can be destructive to host tissues and can occur in the absence of pathogenic infections.&#160;A better understanding of the molecular mechanisms that promote neutrophil trans-epithelial migration through experimental manipulation of the in vitro coculture assay system described herein has significant potential to identify novel therapeutic targets for a range of mucosal infectious as well as inflammatory diseases.

In vitro Coculture Assay to Assess Pathogen Induced Neutrophil Trans-epithelial Migration

Neutrophil trans-epithelial migration in response to mucosal bacterial infection contributes to epithelial injury and clinical disease.&#160;An in vitro model has been developed that combines pathogen, human neutrophils, and polarized human epithelial cell layers grown on transwell filters to facilitate investigations towards unraveling the molecular mechanisms orchestrating this phenomenon.

시험관 내 병원균 유도 호중구 트랜스 상피 이동을 평가하는 공동 문화 분석

Mucosal surfaces serve as protective barriers against pathogenic organisms.&#160;Innate immune responses are activated upon sensing pathogen leading to ...

Expression of Functional Recombinant Hemagglutinin and Neuraminidase Proteins from the Novel H7N9 Influenza Virus Using the Baculovirus Expression System

The baculovirus expression system is a powerful tool for expression of recombinant proteins. Here we use it to produce correctly folded and glycosylated versions of the influenza A virus surface glycoproteins - the hemagglutinin (HA) and the neuraminidase (NA). As an example, we chose the HA and NA proteins expressed by the novel H7N9 virus that recently emerged in China. However the protocol can be easily adapted for HA and NA proteins expressed by any other influenza A and B virus strains. Recombinant HA (rHA) and NA (rNA) proteins are important reagents for immunological assays such as ELISPOT and ELISA, and are also in wide use for vaccine standardization, antibody discovery, isolation and characterization. Furthermore, recombinant NA molecules can be used to screen for small molecule inhibitors and are useful for characterization of the enzymatic function of the NA, as well as its sensitivity to antivirals. Recombinant HA proteins are also being tested as experimental vaccines in animal models, and a vaccine based on recombinant HA was recently licensed by the FDA for use in humans. The method we describe here to produce these molecules is straight forward and can facilitate research in influenza laboratories, since it allows for production of large amounts of proteins fast and at a low cost. Although here we focus on influenza virus surface glycoproteins, this method can also be used to produce other viral and cellular surface proteins.

Here we describe a way to express correctly folded and functional influenza virus surface antigens derived from the novel Chinese H7N9 virus in insect cells. The technique can be adapted to express ectodomains of any viral or cellular surface proteins.

배큘로 바이러스 발현 시스템을 사용하여 소설 H7N9 인플루엔자 바이러스의 기능 재조합 적혈구 응집소와 뉴 라미니다 아제 단백질의 발현

The baculovirus expression system is a powerful tool for expression of  recombinant proteins. Here we use it to produce correctly folded and  glycosylated ...

In Vitro Disassembly of Influenza A Virus Capsids by Gradient Centrifugation

Acid-triggered molecular processes closely control cell entry of many viruses that enter through the endocytic system. In the case of influenza A virus (IAV), virus fusion with the endosomal membrane as well as the subsequent disassembly of the viral capsid, called uncoating, is governed by the ionic conditions inside endocytic vesicles. The early steps in the virus life cycle are hard to study because endosomes cannot be directly accessed experimentally, creating the need for an in vitro approach. Here, we describe a method based on velocity gradient centrifugation of purified virions through a two-layer glycerol gradient, which enables analysis of the IAV core and its stability. The gradient contains a non-ionic detergent (NP-40) in its lower layer to remove the viral membrane by solubilization as the virus sediments toward the bottom. At neutral pH, viral cores are pelleted as stable structures. The major core components, matrix protein (M1) and the viral ribonucleoproteins (vRNPs), can be clearly identified in the pellet fraction by SDS-PAGE. Decreasing the pH to 6.0 or lower in the bottom layer selectively removes M1 from the pellet followed by release of vRNPs at more acidic conditions. Viral protein bands on Coomassie-stained gels can be subjected to densitometric quantification to monitor intermediate states of IAV disassembly. Besides pH, other factors that influence viral core stability can be assessed, such as salt concentration and putative viral uncoating factors, simply by modifying the detergent-containing glycerol layer accordingly. Taken together, the presented technique allows highly reproducible and quantitative analysis of viral uncoating in vitro. It can be applied to other enveloped viruses that undergo complex uncoating processes.

In Vitro Disassembly of Influenza A Virus Capsids by Gradient Centrifugation

Disassembly of influenza A virus cores during virus entry into host cells is a multistep process. We describe an in vitro method to analyze the early stages of viral uncoating. In this approach, velocity gradient centrifugation is used to biochemically dissect the steps that initiate uncoating under defined conditions.

그라데이션 원심 분리에 의해 인플루엔자 A 바이러스 캡시드의 생체 외 분해에

Acid-triggered molecular processes closely control cell entry of many viruses that enter through the endocytic system. In the case of influenza A virus ...

Applying Fluorescence Resonance Energy Transfer (FRET) to Examine Effector Translocation Efficiency by Coxiella burnetii during siRNA Silencing

Coxiella burnetii, the causative agent of Q fever, is an intracellular pathogen that relies on a Type IV Dot/Icm Secretion System to establish a replicative niche. A cohort of effectors are translocated through this system into the host cell to manipulate host processes and allow the establishment of a unique lysosome-derived vacuole for replication. The method presented here involves the combination of two well-established techniques: specific gene silencing using siRNA and measurement of effector translocation using a FRET-based substrate that relies on &#946;-lactamase activity. Applying these two approaches, we can begin to understand the role of host factors in bacterial secretion system function and effector translocation. In this study we examined the role of Rab5A and Rab7A, both important regulators of the endocytic trafficking pathway. We demonstrate that silencing the expression of either protein results in a decrease in effector translocation efficiency. These methods can be easily modified to examine other intracellular and extracellular pathogens that also utilize secretion systems. In this way, a global picture of host factors involved in bacterial effector translocation may be revealed.

Applying Fluorescence Resonance Energy Transfer FRET to Examine Effector Translocation Efficiency by Coxiella burnetii during siRNA Silencing

Investigating the interactions between bacterial pathogens and their hosts is an important area of biological research. Here, we describe the necessary techniques to measure effector translocation by Coxiella burnetii during siRNA gene silencing using BlaM substrate.

적용 형광 공명 에너지 전달 (FRET)을하여 이펙터 전좌 효율을 검사합니다<em&gt; Coxiella burnetii의</em&gt; siRNA를 음소거시

Coxiella burnetii, the causative agent of Q fever, is an intracellular pathogen that relies on a Type IV Dot/Icm Secretion System to establish a ...

Fluorescence-based Neuraminidase Inhibition Assay to Assess the Susceptibility of Influenza Viruses to The Neuraminidase Inhibitor Class of Antivirals

The neuraminidase (NA) inhibitors are the only class of antivirals approved for the treatment and prophylaxis of influenza that are effective against currently circulating strains. In addition to their use in treating seasonal influenza, the NA inhibitors have been stockpiled by a number of countries for use in the event of a pandemic. It is therefore important to monitor the susceptibility of circulating influenza viruses to this class of antivirals. There are different types of assays that can be used to assess the susceptibility of influenza viruses to the NA inhibitors, but the enzyme inhibition assays using either a fluorescent substrate or a chemiluminescent substrate are the most widely used and recommended. This protocol describes the use of a fluorescence-based assay to assess influenza virus susceptibility to NA inhibitors. The assay is based on the NA enzyme cleaving the 2&#8242;-(4-Methylumbelliferyl)-&#945;-D-N-acetylneuraminic acid (MUNANA) substrate to release the fluorescent product 4-methylumbelliferone (4-MU). Therefore, the inhibitory effect of an NA inhibitor on the influenza virus NA is determined based on the concentration of the NA inhibitor that is required to reduce 50% of the NA activity, given as an IC50 value.

We describe the use of a phenotypic fluorescence-based neuraminidase inhibition assay to assess the susceptibility of influenza A and B viruses to the neuraminidase inhibitor class of antivirals.

형광 기반의 뉴 라미니다 아제 억제 분석은 항 바이러스제의 뉴 라미니다 아제 억제제 클래스에 인플루엔자 바이러스의 감수성을 평가하기 위해

The neuraminidase (NA) inhibitors are the only class of antivirals approved for the treatment and prophylaxis of influenza that are effective against ...

Generation of Escape Variants of Neutralizing Influenza Virus Monoclonal Antibodies

Influenza viruses exhibit a remarkable ability to adapt and evade the host immune response. One way is through antigenic changes that occur on the surface glycoproteins of the virus. The generation of escape variants is a powerful method in elucidating how viruses escape immune detection and in identifying critical residues required for antibody binding. Here, we describe a protocol on how to generate influenza A virus escape variants by utilizing human or murine monoclonal antibodies (mAbs) directed against the viral hemagglutinin (HA). With the use of our technique, we previously characterized critical residues required for the binding of antibodies targeting either the head or stalk of the novel avian H7N9 HA. The protocol can be easily adapted for other virus systems. Analyses of escape variants are important for modeling antigenic drift, determining single nucleotide polymorphisms (SNPs) conferring resistance and virus fitness, and in the designing of vaccines and/or therapeutics.

We describe a method by which we identify critical residues required for the binding of human or murine monoclonal antibodies that target the viral hemagglutinin of influenza A viruses. The protocol can be adapted to other virus surface glycoproteins and their corresponding neutralizing antibodies.

인플루엔자 바이러스 단일 클론 항 체를 중화의 탈출 변종의 생성

Influenza viruses exhibit a remarkable ability to adapt and evade the host immune response. One way is through antigenic changes that occur on the surface ...

Measuring Influenza Neutralizing Antibody Responses to A(H3N2) Viruses in Human Sera by Microneutralization Assays Using MDCK-SIAT1 Cells

Neutralizing antibodies against hemagglutinin (HA) of influenza viruses are considered the main immune mechanism that correlates with protection for influenza infections. Microneutralization (MN) assays are often used to measure neutralizing antibody responses in human sera after influenza vaccination or infection. Madine Darby Canine Kidney (MDCK) cells are the commonly used cell substrate for MN assays. However, currently circulating 3C.2a and 3C.3a A(H3N2) influenza viruses have acquired altered receptor binding specificity. The MDCK-SIAT1 cell line with increased &#945;-2,6 sialic galactose moieties on the surface has proven to provide improved infectivity and more faithful replications than conventional MDCK cells for these contemporary A(H3N2) viruses. Here, we describe a MN assay using MDCK-SIAT1 cells that has been optimized to quantify neutralizing antibody titers to these contemporary A(H3N2) viruses. In this protocol, heat inactivated sera containing neutralizing antibodies are first serially diluted, then incubated with 100 TCID50/well of influenza A(H3N2) viruses to allow antibodies in the sera to bind to the viruses. MDCK-SIAT1 cells are then added to the virus-antibody mixture, and incubated for 18 - 20 h at 37 &#176;C, 5% CO2 to allow A(H3N2) viruses to infect MDCK-SIAT1 cells. After overnight incubation, plates are fixed and the amount of virus in each well is quantified by an enzyme-linked immunosorbent assay (ELISA) using anti-influenza A nucleoprotein (NP) monoclonal antibodies. Neutralizing antibody titer is defined as the reciprocal of the highest serum dilution that provides &#8805;50% inhibition of virus infectivity.

Measuring Influenza Neutralizing Antibody Responses to AH3N2 Viruses in Human Sera by Microneutralization Assays Using MDCK-SIAT1 Cells

Influenza neutralizing antibodies correlate with protection of influenza infections. Microneutralization assays measure neutralizing antibodies in human sera and are often used for influenza human serology. We describe a microneutralization assay using MDCK-SIAT1 cells to measure neutralizing antibody titers to contemporary 3C.2a and 3C.3a A(H3N2) viruses following influenza vaccination or infection.

사용 하 여 MDCK SIAT1 세포 분석 실험 측정 인플루엔자 항 체 응답 Microneutralization에 의해 인간의 세라에 A(H3N2) 바이러스를 중화

Neutralizing antibodies against hemagglutinin (HA) of influenza viruses are considered the main immune mechanism that correlates with protection for ...