Characterization of hemagglutinating components on the Anaplasma marginale initial body surface and identification of possible adhesins

Abstract

Interaction of Anaplasma marginale initial bodies with the bovine erythrocyte surface was examined by a direct hemagglutination assay. Purified initial bodies were shown to specifically hemagglutinate bovine erythrocytes but not erythrocytes from nonhost animal species. Hemagglutination was inhibited by treatment of purified initial bodies with trypsin, a-chymotrypsin, or proteinase K but not by treatment with neuraminidase or sodium periodate. Treatment of bovine erythrocytes with a-chymotrypsin or neuraminidase partially inhibited hemagglutination of the treated cells by initial bodies. In contrast, no inhibition occurred after treatment of erythrocytes with trypsin, phospholipases, or sodium periodate or when monosaccharides and disaccharides were used as potential competitive inhibitors. Thus, the initial body receptor is probably a surface protein, whereas the bovine receptor may comprise both protein and carbohydrate. Hemagglutination was unaffected by treatment of initial bodies with monoclonal or polyclonal antibodies raised against the A. marginak 31-kDa (MSP4) major surface polypeptide or non-A. marginake proteins or by treatment with a monoclonal antibody to the A. marginake MSPla neutralization-sensitive epitope. In contrast, antiserum raised against whole A. marginale initial bodies or monospecific antibodies raised against purified A. marginale major surface polypeptides with molecular sizes of 105 (MSPla), 100 (MSPlb), 61, and 36 (MSP2) kDa completely or partially inhibited hemagglutination. These data confirm the proposed surface location of the proteins susceptible to inhibition and suggest that they mediate hemagglutination of bovine erythrocytes. We propose that these surface proteins are possible adhesins.

The immunoprotective Anaplasma marginale major surface protein 2 is encoded by a polymorphic multigene family

“…MSP-2 is conserved between A. marginale and Anaplasma centrale, a less virulent species that induces protection against A. marginale (28,34), and is present in morphologically distinct A. marginale stages in the infected tick vector Dermacentor andersonii (29). Consistent with its conservation in both the intraerythrocytic and tick vector stages is the recent observation that MSP-2 may function as an adhesin for erythrocyte binding (18).…”

Molecular Detection of Tick-Borne Pathogens of the Family Anaplasmataceae in Brazilian Brown Brocket Deer (Mazama gouazoubira, Fischer, 1814) and Marsh Deer (Blastocerus dichotomus, Illiger, 1815)

“…Major surface protein, MSP1a, has been shown to be involved in adhesion for both bovine erythrocytes and tick cells, (McGarey and Allred, 1994; McGarey et al., 1994). The msp1a genes have been used to compare A. marginale geographic strains through molecular weight and the variable number of tandem 23–31 amino acid repeats (de la Fuente et al., 2001c, 2004).…”

A Review of Bovine Anaplasmosis

“…Because of the variation in the repeated portion of the msp1α gene, it has been used as a stable genetic marker for the identification of A. marginale geographical strains (Barbet et al., 1987, 1999; Allred et al., 1990; de la Fuente et al., 2001a). The gene, msp1α , that encodes MSP1a is conserved during the multiplication of the rickettsia in cattle and ticks (Palmer et al., 2001; Bowie et al., 2002) and has been shown to be involved in adhesion to bovine erythrocytes and tick cells (McGarey and Allred, 1994; McGarey et al., 1994; de la Fuente et al., 2001b). Major surface protein 5 is also a highly conserved surface protein that has been proven effective as a diagnostic antigen and is used in a commercially available competitive enzyme‐linked immunosorbent assay (cELISA) (Torioni de Echaide et al., 1998).…”