Cross-reactivity of polyclonal antibodies to antigens from soybean and cowpea crude protein extracts

Abstract

This study was to determine the extent of cross-reactivity between cowpea and soybean crude protein extracts from dry cowpea and soybean seed samples. Four rabbits were immunised subcutaneously with cowpea protein extract and soybean protein extract as immunogen. The immunogen was formulated with saponin as adjuvant in a ratio of 1:1. Antibody titre was determined in immunodiffusion assay for rabbit antisera obtained. Highest titre was recorded for antisera collected on day 28 (four-fold dilution). Analysis of cross-reactivity of the two antigens against anti-cowpea sera showed partial identity of the two antigens hence cross-reactivity was confirmed. The precipitin line with a spur was observed after 24 hours. This indicated that soybean and cowpea have common shared antigenic determinants (epitopes) responsible for the observed cross-reactivity.