A novel mechanism of retrovirus inactivation in human serum mediated by anti-alpha-galactosyl natural antibody.

Type C retroviruses endogenous to various nonprimate species can infect human cells in vitro, yet the transmission of these viruses to humans is restricted. This has been attributed to direct binding of the complement component C1q to the viral envelope protein p15E, which leads to classical pathway-mediated virolysis in human serum. Here we report a novel mechanism of complement-mediated type C retrovirus inactivation that is initiated by the binding of "natural antibody" [Ab] (anti-alpha-galactosyl Ab) to the carbohydrate epitope Gal alpha 1-3Gal beta 1-4GlcNAc-R expressed on the retroviral envelope. Complement-mediated inactivation of amphotropic retroviral particles was found to be restricted to human and other Old World primate sera, which parallels the presence of anti-alpha-galactosyl natural Ab. Blockade or depletion of anti-alpha-galactosyl Ab in human serum prevented inactivation of both amphotropic and ecotropic murine retroviruses. Similarly, retrovirus was not killed by New World primate serum except in the presence of exogenous anti-alpha-galactosyl Ab. Enzyme-linked immunosorbent assays revealed that the alpha-galactosyl epitope was expressed on the surface of amphotropic and ecotropic retroviruses, and Western blot analysis further localized this epitope to the retroviral envelope glycoprotein gp70. Finally, down-regulation of this epitope on the surface of murine retroviral particle producer cells rendered them, as well as the particles liberated from these cells, resistant to inactivation by human serum complement. Our data suggest that anti-alpha-galactosyl Ab may provide a barrier for the horizontal transmission of retrovirus from species that express the alpha-galactosyl epitope to humans and to other Old World primates. Further, these data provide a mechanism for the generation of complement-resistant retroviral vectors for in vivo gene therapy applications where exposure to human complement is unavoidable.

ABO blood groups in two species of peruvian night monkeys (Aotus nancymai and Aotus vociferans)

Foram coletadas amostras de sangue e saliva de 93 animais da espécie Aotus nancymai e 20 de A. vociferans. As amostras de saliva foram testadas para a presença de antígenos ABH humanos, através do teste convencional de inibiçäo da hemaglutinaçäo, o qual nos permitiu classificar 21 A. nancymai e 10 A. vociferans como sendo do grupo B e 72 A. nancymai e 10 A. vociferans como pertencentes ao grupo O. Amostras de soro foram utilizadas para detectar aglutininas naturais do sistema ABO. Os resultados mostraram algumas discrepâncias entre os fenótipos séricos e salivares, como também sugeriram a existência de anticorpos anti-A1 nessas espécies

ABO blood groups in a natural population of chiropotes satanas

Foram coletadas amostras de sangue e saliva de 72 animais da espécie Chiropotes satanas utahicki, capturados na margem esquerda do rio Tocantins, pará (Brasil). As amostras de saliva foram testadas para a presença dos antígenos ABH humanos, através do método convencional de inibiçäo da hemaglutinaçäo. Todos os indivíduos foram classificados como pertencentes ao grupo A. Aglutininas anti-A e anti-B foram pesquisadas em 15 amostras de soro, dos quais 13 apresentaram apenas a aglutinina anti-B e duas näo apresentaram nenhum dos anticorpos. Amostras de hemácias foram testadas pelo método de eluiçäo, para verificar a presença de antígenos A e B humanos. Os resultados confirmam a presença de B-like, detectado em outros macacos do Novo Mundo e sugere a ocorrência de A-like

Behavioral and endocrine consequences of heterosexual pair formation in squirrel monkeys.

The South American squirrel monkey (Saimiri sciureus) typically lives in large social groups containing several individuals of all age/sex categories. When living in established heterosexual pairs, reproduction in this seasonally breeding primate is poor. We attempted to induce breeding activity in pair-housed monkeys by forming new heterosexual pairs just prior to the breeding season. Breeding readiness, as reflected in behavior and gonadal hormones, was induced in males, but not in females. Males also showed persistent increases in cortisol levels following formation of new heterosexual pairs; females did not. The results indicate that social stimulation provided by a single novel female is sufficient to enhance breeding readiness in male squirrel monkeys. Females, on the other hand, are apparently unresponsive to a single male whether novel or familiar; this may account for the poor reproductive success in squirrel monkeys housed in heterosexual pairs.

Serum oestradiol, progesterone, chorionic gonadotrophin and prolactin concentrations during pregnancy in the Bolivian squirrel monkey (Saimiri sciureus).

Concentrations of chorionic gonadotrophin gradually increased during early pregnancy, reached maximum values at mid-gestation, then declined to low levels. Oestradiol-17 beta concentrations were relatively low (300-600 pg/ml) during early pregnancy, increased thereafter to high levels (10-35 ng/ml), and then appeared to decline towards term. Concentrations of progesterone were constant (100-200 ng/ml) for the first 15 weeks of gestation, suggesting that sequential measurements of progesterone could be used to diagnose early pregnancy. Prolactin concentrations rose during pregnancy, reaching maximum values at term.

Rapid cortisol and corticosteroid-binding globulin responses during pregnancy and after estrogen administration in the squirrel monkey.

Plasma cortisol and corticosteroid-binding globulin (CBG) levels were assessed in pregnant squirrel monkeys and in intact and castrated males after estrogen administration. Pregnant females showed a rapid and dramatic rise in cortisol and CBG during the first 8 weeks after conception. Estrogen treatment also caused marked elevations in cortisol and CBG. Cortisol levels increased significantly by 24 h after estrogen injection and remained elevated for 6 weeks of treatment, but a relatively greater rise in CBG resulted in a higher CBG/cortisol ratio. The data support prior research indicating that estrogen can simultaneously stimulate adrenal output and the compensatory binding of circulating cortisol by increased CBG synthesis. In addition, it appears that even in the absence of exogenous treatment, the pituitary-adrenal axis of male squirrel monkeys is stimulated by estrogen derived either from the testes or by the peripheral conversion of testosterone to estrogen.

Serum hormone patterns during abortion in the Bolivian squirrel monkey.

Serum measurements of chorionic gonadotropin (CG), estradiol (E-2) and progesterone (P) were used to describe patterns of hormonal change in Bolivian squirrel monkeys undergoing spontaneous abortion. During early pregnancy, serum CG levels gradually increased, reaching maximum levels at the end of the first 50 days of pregnancy (range: 200-1964 ug protein/ml). E-2 concentrations also increased to high levels (10-30 ng/ml) toward the end of pregnancy, while serum P remained fairly constant at levels above 100 ng/ml. A gradual decline in serum hormone concentrations was observed in aborting animals. CG levels declined to less than 100 ug protein/ml while E-2 and P decreased to concentrations characteristic of nonpregnant cycling animals, less than 500 pg/ml and 20 ng/ml respectively. The data suggest that two weekly measurements of CG and E-2 could be used to identify monkeys undergoing abortion and those which have already aborted.

Plasma concentrations of oestradiol-17 beta, oestrone, progesterone and testosterone during the ovarian cycle of the owl monkey (Aotus trivirgatus).

Oesterone, oestradiol-17 beta, progesterone and testosterone were measured by radioimmunoassay in daily plasma samples throughout the ovarian cycle in 4 female owl monkeys. Clearly defined peaks of oestradiol-17 beta occurred at intervals of 15.5 +/- 0.56 days and confirmed the length of the cycle reported previously. Progesterone rose on the day on the day of the oestradiol-17 beta to reach a maximum 4--6 days later, thereafter decreasing gradually to low levels before the onset of the next cycle. On the basis of these data the follicular and luteal phases were estimated to be 6 and 10 days respectively. Osterone and testosterone peaks preceded that of progesterone by 24 and remained elevated throughout the luteal phase. Plasma concentrations of all steroids were markedly higher than for other primate species. Vaginal cytology was considered unsuitable as an indicator of the stage of the ovarian cycle.