High rates of asthma in children of lower socioeconomic circumstances is thought to be related to the presence of allergens and antigens of the German Cockroach Blatetella germanica, which often infests public housing developments. Several major allergens, including 96, 56 and 23 kD molecular weight proteins have been characterized; most research has been performed with extracts of cockroach whole bodies. Investigators at the USDA were interested in the potential immunological activity of cockroach debris left in dwellings after treatment with various insecticides and cleaning agents. However, due to the limited quantities of allergic serum available from pediatric patients, an allergen based system was not realistic. USDA provided source materials of cockroach whole bodies as well as samples of cockroach debris collected from specially designed and constructed dwellings at the USDA in Gainesville, FL. LRR prepared freeze-dried extracts of these materials; using 6 rabbits, LRR raised IgG antibodies to a variety of proteins in cockroach debris. Collaborators at the Arkansas Children's Hospital (ACH) determined that the cockroach debris contained the known allergens and these allergens were detected as antigens by the rabbit antibodies. Qualitative loss of binding activity of the rabbit antibodies correlated with loss of IgE binding in immunoblotting experiments created by various treatments of the LRR extracts. To attempt to quantitate of this loss, an ELISA type assay has been developed at LRR using the rabbit antibody. Methods of sampling cockroach infested areas before and after treatment with various pesticides and cleaners are being attempted at the USDA facilities, to be tested for residual immunological activity in the rabbit antibody ELISA. Following detection of antigenic changes in the ELISA, samples will be evaluated at ACH for allergenic or IgE activity. Plans include transferring the ELISA system to USDA if the allergen destruction parallels rabbit antibody ELISA response. This will permit further development in measuring the effects of pesticides and cleaners by destroying potential allergens that remain after extermination of the cockroaches; this in turn will reduce potential exposure to asthma creating situations for children.
