Figure 4.

Protective capacity of hypermutated and germ-line IgGs in mice. SCID mice were reconstituted with graded doses of monoclonal antibodies of the IgG2a subclass, which were either devoid of somatic mutations (open symbols) or hypermutated (filled symbols). Five hours later mice were i.v. challenged with 10⁸ pfu of VSV-IND. After 4 days the brains of surviving mice were assessed for the presence of virus. Mice without detectable virus were scored as being protected. Groups of three mice were tested; deviating numbers of tested animals are given in parentheses. (A) Analysis of IgGs using V gene fragments belonging to the V_HQ52 and the V_κ19–28 families. The germ-line antibodies 41.11 (□), 41.2 (▵), and 41.9 (○) were isolated from primary responses 4 days after infection. The hypermutated antibodies VI10 (■) and VI49 (●) were isolated, respectively, from a secondary response 12 days after infection and from a hyperimmune response 150 days after infection. (B) Analysis of IgGs using the V_H61–1P germ-line gene fragment belonging to the V_H7183 family and the J_H2 segment. The germ-line antibodies 41.6 (□) and 51.3 (▵) were isolated from primary responses 4 and 5 days after infection, respectively. The germ-line antibody VI26 (□) was isolated from a secondary response 12 days after infection. The hypermutated antibody VI43 (●) was isolated from a hyperimmune response 150 days after infection.