Published customer image: . Baby rabbit serum used as a source of complement in a complement bactericidal assay. Image caption: . Killing of S. Typhimurium by total IgG, IgM and IgA from HIV-uninfected and HIV-infected sera. Log growth phase S. typhimurium D23580 was added to a mixture of the purified antibodies and 75% BRS. The log 10 proportion of the starting number of bacteria remaining after 180 minutes was determined on LB agar. To obtain total antibody of each isotype (IgG, IgM and IgA), serum was incubated sequentially with combinations of human IgA and IgM affinity matrices and protein G affinity matrix to remove IgA, IgM and IgG respectively. Sera used were HIV-uninfected (HIV-ve bactericidal, n = 3), HIV-infected bactericidal (HIV+ve bactericidal, n = 4) and HIV-infected inhibitory (HIV+ve inhibitory, n = 5) sera. Each line represents killing by purified total IgG, IgM or IgA antibodies from one serum. Data shown are from a single representative experiment, where each of the three independent experiments was performed in technical triplicates. From: Goh YS, Necchi F, O Shaughnessy CM, Micoli F, Gavini M, Young SP, et al. (2016). Bactericidal Immunity to Salmonella in Africans and Mechanisms Causing Its Failure in HIV Infection. PLoS Negl Trop Dis 10(4): e0004604.