Species-dependent immunological differences between various mammalian cardiac tropomyosins

Antisera were produced from guinea-pigs against purified pig or rat cardiac tropomyosins and antigen-antibody interactions were analyzed by the micro-complement fixation technique. Immunoadsorption with purified tropomyosins coupled with CN Br-activated Sepharose 4B enabled us to establish that these antisera were only specific to tropomyosin and not to other contractile proteins. Direct cross-reactions and competition experiments performed with both the above antisera indicated quantitative differences in the maximum amount of complement fixed by tropomyosins from various heterologous species (man, beef, pig, rabbit, rat and mouse). These data provide direct evidence that mammalian cardiac tropomyosin is species-specific.