Shared and specific allergenic and antigenic components in the two sexes of American cockroach—Periplaneta americana

The whole body extracts (WBEs) of female and male cockroaches (Periplaneta americana; Pa) were prepared separately to study the specific and/or shared allergenic and antigenic components in the two sexes. These two extracts were skin‐tested on 170 respiratory allergy patients and 52 (30–6%) of them elicited a markedly positive cutaneous reaction (2+ to 4+) to any one or both the WBEs. Of these 52 patients, 32 (61·5%) produced a 2+ to 4+ response to only one, and the remaining 20 (38·5%) to both the extracts. In female and male RASTs to Pa both the extracts produced dose‐related inhibition. Using rabbit anti‐Pa female serum: (1) immuno‐diffusion experiments resulted in lines of identity with the two extracts, and (2) the two‐dimensional immunoelectrophoresis of Pa female and Pa male WBEs elicited 12 and nine precipitin peaks, respectively. In partial purification studies, only fraction Pa(F)III (∼ 50 kD) of Pa female WBE and Pa(M)I ( 600 kD) and Pa(M)III (∼ 50 kD) fractions of Pa male WBE revealed significant allergen activity both on skin testing and also in RAST inhibition studies. These results provide evidence for the presence of shared as well as specific allergenic and antigenic components in the two sexes of American cockroach.