Immunogenicity of the histidine-to-tyrosine staphylococcal enterotoxin B mutant protein in C3H/HeJ mice.

Staphylococcal enterotoxin B (SEB) is a common cause of food poisoning and toxic shock. A safe and effective vaccine is needed to protect against the superantigenic effects of this toxin. We previously constructed and produced an apparently nontoxic SEB mutant having four histidine-to-tyrosine substitutions in positions 12, 32, 105, and 121. In the present study, we found that this H1.2.3.4 SEB mutant had low toxicity, was able to induce high levels of specific IgG antibodies, and protected mice in both the actinomycin D-primed and intranasal SEB intoxication model systems, despite the absence of detectable specific IgM and IgA antibodies. We propose further development of the H1.2.3.4 recombinant protein as a potential anti-SEB vaccine candidate.