title: Antibody response of mice to lactate dehydrogenase-elevating virus during infection and immunization with inactivated virus.
abstract: BALB/c and Swiss mice were infected with lactate dehydrogenase-elevating virus (LDV) or immunized with glutaraldehyde-inactivated or ether-extracted virus and their plasma was monitored for anti-LDV IgG and IgM levels by ELISA and indirect fluorescent antibody staining, for neutralizing antibodies, for sensitized antibody-virus complexes, for immune complexes, and for total plasma IgG and IgM. In infected mice, anti-LDV IgM was transiently formed during the first 2 weeks post infection (p.i.) but only at a low level. Anti-LDV IgG was produced in a biphasic manner with an initial peak at about 10 days p.i. and a secondary rise reaching a maximum level 30-80 days p.i. which was retained throughout the persistent phase of infection. The concomitant appearance of comparable levels of low molecular weight immune complexes suggests that most anti-LDV IgG was complexed with LDV proteins. Also, as early as 10 days p.i., infectious antibody-LDV complexes developed, which were neutralizable by rabbit anti-mouse IgG, whereas antibodies that neutralize the infectivity of exogenously added LDV appeared only 1-2 months p.i. Throughout infection, most of the anti-LDV IgG was directed to VP-3, the envelope glycoprotein of LDV, which was found to exist in at least 10 distinct forms ranging in molecular weight from 24 to 42 kDa. Anti-LDV IgG levels as high as those observed in infected mice developed in mice immunized with inactivated LDV. Antibodies to glutaraldehyde-inactivated LDV were also mainly directed to VP-3, but exhibited no neutralizing activity. The polyclonal B cell activation associated with a persistent LDV infection and the formation of immune complexes were not observed in mice immunized with inactivated virus.
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000096:biosynthesis*; D000936:Antigen-Antibody Complex / Q000096:biosynthesis; D005260:Female; D007074:Immunoglobulin G / Q000032:analysis; D007772:Lactate dehydrogenase-elevating virus / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D014036:Togaviridae Infections / Q000276:immunology*; D014613:Vaccines, Attenuated / Q000276:immunology*; D014764:Viral Proteins / Q000276:immunology; D014765:Viral Vaccines / Q000276:immunology*
chemical_list: D000914:Antibodies, Viral; D000936:Antigen-Antibody Complex; D007074:Immunoglobulin G; D014613:Vaccines, Attenuated; D014764:Viral Proteins; D014765:Viral Vaccines