Research Article
Shivanandappa KC, Jagannathan
Abstract
Heat Labile toxin (HLT) is a mouse lethal toxin produced by all virulent Bordetella pertussis species. B. pertussis cells were dermo necrotizing and lethal when injected in to animals. Therefore in the present study the biological property of heat labile toxin of B. pertussis strain 134 was assessed before and after heat inactivation. The result found in SDS PAGE analysis of non-heat inactivated sample (NIS) shown apparent molecular mass of 102 kDa whereas it is absent in the Heat inactivated sample (HIS). The Mouse Weight Gain Test (MWGT) results shown that, after the culture cells were heated at 56ºC for 30 min (HIS) detoxification sample shown good weight gain in the mouse .In case of in NIS there was a decreased in weight, death of mice was also observed. The antigenic property was tested by agglutination test were found to be good in both samples proved the presence of factor 1and 3. Further the HIS and NIS samples were evaluated through ischemic and DNT tests, the sample NIS was tested in the guinea pig and mice, induced hemorrhagic and dermonecrosis reactions on the inoculated region of skin. All dermonecrotizing activity and a large part of the lethal toxicity were observed in guinea pig and mice. There was no such reactions were seen in case of HIS sample. If the cells were heated above 56ºC the virulence activities was substantially diminished. These biological effects of organisms are now known to be caused by Heat labile toxin which is also called dermonecrotic toxin. Hence HLT should be detoxified at 56ºC at 30 minutes is most preferred, during the production of Whole Cell Pertussis Vaccine.