Proliferative T Cell Response to Botulinum Toxin Type A in Mice
Clostridium botulinum can be divided into seven types, designated A to G. Each type produces an immunologically distinct neurotoxin. For more than 40 years, immunisation with botulinum toxoid has been used to protect laboratory workers at risk for botulism due to contact with the neurotoxins. However, the toxoid preparations used are relatively crude producing undesirable local and systemic reactions. The current pentavalent (ABCDE) toxoid manufactured by the Michigan Department of Public Health using the same methodology as Parke, Davis and Co induces significantly improved response to type B but not to type A and E. Furthermore, a 25-week period rather than 12 weeks is required to achieve a protective level and the range of antibody titres among individuals who received the same number of immunisations is very wide (1). Therefore, it appears that an understanding of the B and T helper cell responses induced by the toxoid would help in the design of improved vaccines. As a first step, we compared the in vitro proliferative T cell response induced in mice by botulinum toxoid in the presence or absence of alum. Secondly, we examined sera from immunised mice for neutralising antibody response and showed that increased neutralising antibody titre correlates with the induction of good proliferative T cell response.
KeywordsTitration Gelatin Thymidine Clostridium Tetanus
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