title: Antiviral immune responses in CTLA4 transgenic mice.
abstract: The role of B7 binding CD28 in the regulation of T- and B-cell responses against viral antigens was assessed in transgenic mice expressing soluble CTLA4-Hgamma1 (CTLA4-Ig tg mice) that blocks B7-CD28 interactions. The results indicate that transgenic soluble CTLA4 does not significantly alter cytotoxic T-cell responses against replicating lymphocytic choriomeningitis virus (LCMV) or vaccinia virus but drastically impairs the induction of cytotoxic T-cell responses against abortively replicating vesicular stomatitis virus (VSV). While the T-independent neutralizing immunoglobulin M (IgM) responses were within normal ranges, the switch to IgG was reduced 4- to 16-fold after immunization with abortively replicating VSV and more than 30-fold after immunization with an inert VSV glycoprotein antigen in transgenic mice. IgG antibody responses to LCMV, as detected by enzyme-linked immunosorbent assay and by neutralizing action, were reduced about 3- to 20-fold and more than 50-fold, respectively. These results suggest that responses in CTLA4-Ig tg mice are mounted according to their independence of T help. While immune responses to nonreplicating or poorly replicating antigens are in general most dependent on T help and B7-CD28 interactions, they are most impaired in CTLA4-Ig tg mice. The results of the present experiments also indicate that highly replicating viruses, because of greater quantities of available antigens and by inducing as-yet-undefined factors and/or cell surface changes, are capable of compensating for the decrease in T help caused by the blocking effects of soluble CTLA4.
authors.affiliation: Institute of Experimental Immunology, University Hospital, Zurich, Switzerland.
authors.forename: C
authors.initials: C
authors.lastname: Zimmermann
authors.forename: P
authors.initials: P
authors.lastname: Seiler
authors.forename: P
authors.initials: P
authors.lastname: Lane
authors.forename: R M
authors.initials: RM
authors.lastname: Zinkernagel
mesh_terms: D000069594:Abatacept; D000818:Animals; D000914:Antibodies, Viral / Q000276:immunology*; D015703:Antigens, CD; D000943:Antigens, Differentiation / Q000235:genetics / Q000276:immunology*; D060908:CTLA-4 Antigen; D002460:Cell Line; D018796:Immunoconjugates; D008217:Lymphocytic choriomeningitis virus / Q000276:immunology*; D008562:Membrane Glycoproteins; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D014616:Vaccinia virus / Q000276:immunology*; D014721:Vesicular stomatitis Indiana virus / Q000276:immunology*; D014759:Viral Envelope Proteins / Q000276:immunology
chemical_list: D000914:Antibodies, Viral; D015703:Antigens, CD; D000943:Antigens, Differentiation; D060908:CTLA-4 Antigen; C556707:Ctla4 protein, mouse; C028391:G protein, vesicular stomatitis virus; D018796:Immunoconjugates; D008562:Membrane Glycoproteins; D014759:Viral Envelope Proteins; D000069594:Abatacept