Gangliosides as a possible receptor on the bovine erythrocytes for Theileria sergenti.

Abstract

To elucidate whether or not gangliosides on the bovine erythrocytes serve as a receptor for Theileria sergenti merozoites, the reactivities of the T. sergenti piroplasms with gangliosides were studied by the liposome agglutination test. The parasites reacted weakly with I-active ganglioside containing N-acetylneuraminic acid (NeuAc) and strongly with I-active ganglioside containing N-glycolylneuraminic acid (NeuGc). However, none of the other gangliosides expressed on the bovine erythrocytes, such as GM3 (NeuAc), GM3 (NeuGc), sialosylparagloboside (SPG) (NeuAc), SPG (NeuGc), i-active ganglioside (NeuAc), and i-active ganglioside (NeuGc), were recognized. After infection with T. sergenti, furthermore, the content of I-active ganglioside (NeuAc) was less (p < 0.05), and I-active ganglioside (NeuGc) content was much less in the erythrocytes (p < 0.01), though the contents of other NeuAc- and NeuGc-containing gangliosides did not so vary with T. sergenti infection. These results suggest that the parasites recognize the I-active ganglioside as their receptor and bind preferentially to NeuGc-carrying I-active ganglioside rather than to NeuAc-type in the target cell membranes, and that the reduction of the contents of I-active gangliosides (NeuAc and NeuGc) on the erythrocytes was related to T. sergenti infection.