Identification and location of albumin-like antigens in third-stage larva of W. bancrofti, in adult forms of Litomosoides chagasfilhoi and in the free-living nematode Caenorhabditis elegans.

Antigens resembling those of host proteins have been identified on the surface of several filarial parasites, such as immunoglobulins and serum albumins. The origin of albumin-like antigens on filarial parasites remains unclear. Several authors suggested that they have been adsorbed, or that they were metabolic waste products from nutritional utilization of human albumin, or perhaps a contamination with human products. This study searched for human albumin-like antigens by Western blot and ultrastructural analyses on filarial parasites, third stage of W. bancrofti and adult females of Litomosoides chagasfilhoi, and on the free-living Caenorhabditis elegans nematode. Our results showed approximately 67kDa proteins recognized by anti-human albumin antibodies on extracts and excretory-secretory (ES) products of the third-stage W. bancrofti. Similar albumin-like proteins were also detected on the filarial parasite L. chagasfilhoi and on C. elegans extracts. The immunocytochemistry analysis showed human albumin-like antigens on similar tissues of these nematodes. These results provide evidence that these proteins have antigenic similarity and similar distribution in nematodes tissues. Our observations suggest that albumin-like antigens presented on filarial parasites are not acquired from the host, but rather are shared antigenic determinants found even in the third-stage larvae recovered from the invertebrate host.

Somatic antigens from male and female adults of Setaria cervi: immune reactions in guinea pigs.

Antigens obtained from adult female Setaria cervi were more protective than those of males against the development of microfilaremia in guinea pigs (transplanted with 10 S. cervi). In high dose levels (2 ml 500 microliters/ml) significant resistance was induced by antigens from male (52% of protection) and female (62% of protection) worms. The antigens from female worms were effective (40% protection) at low dose level (2 ml 50 microliters/ml) also.

Somatic antigens from male and female adults of Setaria cervi: immune reactions in guinea pigs

Los antígenos de Setaria cervi hembra son más eficaces que los de macho para evitar el desarrollo de microfilaremia en cabayos (10 parásitos por individuo). Con dosis altas (2ml 500 µl) se obtuvo resistencia significativa a partir de antígenos de parásitos machos (52% de protección) hembras (62%). Los antígenos de hembra tambíen protegieron (40% con dosis bajas (2ml 50 µ/ml)

Mansonella ozzardi in Haiti. IV. Evaluation of antibody reactivity to heterologous antigens.

Sera from individuals in an area of Haiti endemic for Mansonella ozzardi were analyzed for reactivity to antigens of Brugia pahangi, Dirofilaria immitis, Mansonella llewellyni or Ascaris lumbricoides using either an enzyme-linked immunosorbent assay or an indirect immunofluorescent antibody test. IgM and IgG reactivity to all antigens was observed with sera from both microfilaremic and amicrofilaremic individuals when compared to reactivity of sera from individuals from nonendemic areas. Antibody reactivity to B. pahangi was greater than that to other antigens. IgG reactivity of sera from endemic patients to filarial antigens was consistently greater than that of IgM. Antibody reactivity was not correlated with age or microfilarial density.

Comparison of heterologous adult Brugia malayi and homologous Onchocerca volvulus antigen in the enzyme-linked immunosorbent assay (ELISA) for Guatemalan onchocerciasis.

To determine the susceptibility of a heterologous filarial antigen for measuring Onchocerca volvulus antibodies, worms were compared using an enzyme-linked immunosorbent assay (ELISA) test. Control serum samples from helminth-free U.S. residents and from helminth-infected but filariae-free Salvadoran residents were tested and compared with serum obtained from microfilariae-positive and -negative Guatemalan residents living in an area of endemic onchocerciasis. The results showed that none of the sera from U.S. residents had positive O. volvulus ELISA titers (greater than or equal to 1:160); however, 8.51% (4/47) had positive B. malayi ELISA titers (greater than or equal to 1:640). The geometric mean titers with the B. malayi ELISA test were higher than with the O. volvulus ELISA test--in sera from 47 U.S. residents (1:219 vs. 1:49), from 108 Salvadoran residents (1:92 vs. 1:71), and from 145 microfilariae-negative (1:539 vs. 1:167) and 303 microfilariae-positive (1:1,270 vs. 1:561) Guatemalan residents. The B. malayi ELISA test exhibited slightly less sensitivity than the homologous O. volvulus ELISA test; nevertheless, a good correlation (r = 0.74) was found between the 2 test antigens, indicating that the B. malayi antigen could be used to measure O. volvulus antibodies.