Abstract
The antibody specific for human alpha smooth muscle actin is known to be useful for detection of similar antigen in several species, but not tested for the camel. The present study tested this antibody for cross-reactivity with the smooth muscle of the small intestine of the camel using alkaline phosphatase anti-alkaline phosphatase technique. Formalin fixed specimens were obtained from the small intestine of 5 male dromedary camels (8-10 years old). The specimens were processed and paraffin sections were prepared. Paraffin Sections from human pharyngeal tonsils were stained in parallel with camel sections as a positive control. The monoclonal mouse anti-human alpha smooth muscle actin IgG2a, Kappa (Dako Gloostrup, Denmark) was applied on the sections. The reactivity was developed using fast red. The antibody reacted with the smooth muscles in the camel small intestine. No non specific reactions were observed. The intensity of the reaction was variable in the same section. The smooth muscles of the lamina muscularis mucosae, as well as, those in the wall of the blood vessels of the tunica submucosa showed more intense reaction than that of the tunica muscularis. The variation in the intensity of the reaction referred to the amount of alpha actin in the smooth muscle. The degree of reactivity in the tunica muscularis was variable. Thin layer of alpha smooth muscle actin positive cells observed between the intestinal crypts and in the core of intestinal villi. The striated border (microvilli) of the columnar epithelium covering the intestinal villi expressed alpha smooth muscle actin positive reaction. The camel smooth muscle actin and that of the human may show some similarity in their antigenic structure so that the monoclonal mouse anti- human alpha smooth muscle actin can also identify the alpha smooth muscle actin in the camel.

Key words: alpha smooth muscle actin, jejunum, camel, immunohistochemistry