Studies on the neutralization of herpes simplex virus. X. Demonstration of complement-requiring neutralizing (CRN) and slow-reacting CRN (s-CRN) antibodies in late IgG.
A sample of late IgG from a rabbit hyperimmunized with herpes simplex virus was analyzed for neutralizing (N) and complement-requiring neutralizing (CRN) antibodies. In a usual endpoint test, N and CRN titers were 1: 40 and 1: 160, respectively, but when virus-IgG mixtures were incubated at 0 C overnight before addition of complement (C), an endpoint of 1:1280 was obtained. Virus sensitized at 0 C overnight required more C for inactivation than did sensitized virus formed earlier. Sensitization kinetic curve experiments employing a proper initial virus concentration, which permitted differentiation of sensitized viruses requiring different amounts of C, indicated that formation of sensitized virus detectable only with a relatively large amount of C proceeded slowly at IgG dilutions where the ordinary CRN antibody requiring a smaller amount of C was negligible. The results strongly suggested that the IgG sample contained slow-reacting CRN (s-CRN) antibody in excess of the hitherto known CRN antibody. As to the mechanism of formation of s-CRN complexes, experiments failed to prove the occurrence of complexes initially insensitive to C, and it appears more likely that s-CRN antibody has a comparatively low avidity for virus.
D000818:Animals; D000914:Antibodies, Viral / Q000276:immunology*; D003080:Cold Temperature; D003165:Complement System Proteins / Q000276:immunology*; D005260:Female; D007074:Immunoglobulin G / Q000276:immunology*; D007700:Kinetics; D009500:Neutralization Tests; D012639:Seeds / Q000382:microbiology; D018139:Simplexvirus / Q000276:immunology*; D013997:Time Factors
D000914:Antibodies, Viral; D007074:Immunoglobulin G; D003165:Complement System Proteins