chemical-conjugation-purified-dec-205-directed-antibody-with-full

Chemical Conjugation of a Purified DEC-205-Directed Antibody with Full-Length Protein for Targeting Mouse Dendritic Cells <em>In Vitro</em> and <em>In Vivo</em>

Targeted antigen delivery to cross-presenting dendritic cells (DC) in vivo efficiently induces T effector cell responses and displays a valuable approach ...

Helmholtz Centre for Infection Research

Otto-von-Guericke University Magdeburg

Downstream processing and formulation of viral vaccines employs a large number of different unit operations to achieve the desired product qualities. The complexity of individual process steps involved, the need for time consuming studies towards the optimization of virus yields, and very high requirements regarding potency and safety of vaccines results typically in long lead times for the establishment of new processes. To overcome such obstacles, to enable fast screening of potential vaccine candidates, and to explore options for production of low cost veterinary vaccines a new platform for whole virus particle purification and formulation based on magnetic particles has been established. Proof of concept was carried out with influenza A virus particles produced in suspension Madin Darby canine kidney (MDCK) cells. The clarified, inactivated, concentrated, and diafiltered virus particles were bound to magnetic sulfated cellulose particles (MSCP), and directly injected into mice for immunization including positive and negative controls. We show here, that in contrast to the mock-immunized group, vaccination of mice with antigen-loaded MSCP (aMSCP) resulted in high anti-influenza A antibody responses and full protection against a lethal challenge with replication competent influenza A virus. Antiviral protection correlated with a 400-fold reduced number of influenza nucleoprotein gene copies in the lungs of aMSCP immunized mice compared to mock-treated animals, indicating the efficient induction of antiviral immunity by this novel approach. Thus, our data proved the use of MSCP for purification and formulation of the influenza vaccine to be fast and efficient, and to confer protection of mice against influenza A virus infection. Furthermore, the method proposed has the potential for fast purification of virus particles directly from bioreactor harvests with a minimum number of process steps towards formulation of low-cost veterinary vaccines, and for screening studies requiring fast purification protocols.

A cell culture-derived whole virus influenza A vaccine based on magnetic sulfated cellulose particles confers protection in mice against lethal influenza A virus infection.

Acquisition of effector functions in T cells is guided by transcription factors, including NF-κB, that itself is tightly controlled by inhibitory proteins. The atypical NF-κB inhibitor, IκB is involved in the development of Th1, Th17, and regulatory T (Treg) cells. However, it remained unclear to which extend IκB contributed to the acquisition of effector function in T cells specifically responding to a pathogen during in vivo infection. Tracking of adoptively transferred T cells in Listeria monocytogenes infected mice antigen-specific activation of CD4 T cells following in vivo pathogen encounter to strongly rely on IκB . While IκB was largely dispensable for the acquisition of cytotoxic effector function in CD8 T cells, IκB -deficient Th1 effector cells exhibited significantly reduced proliferation, marked changes in the pattern of activation marker expression, and reduced production of the Th1-cell cytokines IFN-γ, IL-2, and TNF-α. Complementary in vitro analyses using cells from novel reporter and inducible knockout mice revealed that IκB predominantly affects the early phase of Th1-cell differentiation while its function in terminally differentiated cells appears to be negligible. Our data suggest IκB as a potential target to modulate specifically CD4 T-cell responses.

Sarah Frentzel

Immune Regulation Group

Helmholtz Centre for Infection Research

Chemical Conjugation of a Purified DEC-205-Directed Antibody with Full-Length Protein for Targeting Mouse Dendritic Cells In Vitro and In Vivo