FIG. 4.

Serum anti-SIV antibodies. (A) Anti-SIV IgG titers in the sera of monkeys immunized with SabRV1-SIV and SabRV2-SIV. Seven cynomolgus macaques were inoculated intranasally with SabRV1-SIV at weeks 0 and 2 (indicated by ▵ below) and given intranasal boosters at weeks 19 and 21 with SabRV2-SIV (indicated by ▴ below). Monkeys are labeled as follows: 25231, ▪; 27244, ●; 27250, ▴; 27253, ♦; 27270, □; 27273, ○; and 28508, ▵. Titers indicated are reciprocal dilutions. A titer of 1 is stringently defined as an ELISA optical density reading 3 standard deviations above the average optical density for a group of negative-control monkeys (see Materials and Methods). (B) Anti-SIV IgA titers in the sera of SabRV1-SIV- and SabRV2-SIV-immunized monkeys. Symbols are as noted above. A clear anemnestic IgA response is evident for all seven macaques after SabRV2-SIV immunization at week 19. Symbols are as for panel A.