In vivo study of mIgM and mIgD cross-linking on murine B cells

In this study, we have analysed in mice the effects on the immune response of in vivo treatment with different rat monoclonal antibodies (MoAb) against IgM and IgD. Although the effects of IgD cross-linking have been studied already, no attempt has been made to characterize the effects of in vivo IgM crosslinking, probably because of the higher IgM serum levels compared to IgD. We have used a panel of nine monoclonal rat anti-mouse IgM and three anti-IgD antibodies and we have characterized their isotypes, avidities, immunoglobulin (Ig) cross-linking and internalization abilities. Our results show that injection of mice with some rat MoAb against IgM led to an important decrease of IgM serum level and internalization of membrane IgM (mIgM) on almost all B cells. Similarly, treatment with a high-avidity anti-IgD antibody induced disapperance of mIgD on B cells. Treatment with rat MoAb against IgM or IgD led to a synthesis of specific antibodies and there was a direct relationship between the Ig internalization abilities of rat MoAb and the induction of specific antibody production. Finally, treatment with a high-avidity rat MoAb against IgD induced a polyclonal IgE and IgG1 secretion. The significance of these results on mIg receptor functions is discussed

Infecção experimental em suínos jovens com Leptospira interrogans sorovar wolffi: determinação de parâmetros bioquímicos Experimental infection by Leptospira interrogans serovar wolffi in young pigs: determination of biochemical parameters

Um estudo sobre infecção experimental foi realizado em oito suínos, com idade média de 90 dias, machos castrados, da raça Wessex, e distribuídos em dois grupos de quatro suínos cada. Durante 36 dias, foram analisadas as alterações bioquímicas nos soros dos suínos dos dois grupos. O Grupo I foi mantido como testemunho e recebeu 5,0mL de solução fisiológica estéril por via intravenosa (veia cava craniana) e, no Grupo II, os suínos foram inoculados pela mesma via com 5,0mL de cultura de Leptospira interrogans sorovar wolffi , amostra L-10 selvagem isolada de tatu (Dasypus novemcinctus), contendo 1,0 x 10(8) leptospiras/mL. A partir do terceiro dia após a inoculação e em intervalos de 72 horas até o décimo oitavo dia, foram feitas coletas de sangue, sem anticoagulante, dos animais inoculados e testemunhas. Os parâmetros bioquímicos analisados foram: bilirrubina total, direta e indireta, ácidos graxos, glicose e proteínas plasmáticas. Foi detectado um aumento da bilirrubina direta no terceiro dia e um aumento no sexto dia da bilirrubina total e indireta após a inoculação. As dosagens de glicose, ácidos graxos e proteínas plasmáticas apresentaram uma diminuição a partir do terceiro dia da inoculação. Com os resultados obtidos, pode-se concluir que o aumento das taxas de bilirrubinas levam a uma definição de um diagnóstico de hemólise aguda, e que a hipoglicemia, a hipolipidemia e a hipoproteinemia podem estar relacionadas com lesões hepáticas e a uma septcemia.Todas as dosagens em todos os animais retornaram aos seus valores normais a partir do décimo quinto dia.<br>Eight, 90 days old pigs, of the Wessex lineage all castrated male were used in experiment, divided into two groups of four animals. Biochemical alterations in the serum of the animals were analyzed in both groups during 36 days. Control (Group I) received 5.0mL of a 0.9% sterile sodium chloride solution by intracranial vein injection; Group II animals were inoculated by the same way with 5.0mL of a cell culture containing 1.0x10(8)cells/mL of Leptospira interrogans sorovar wolffi, wild strain L-10, isolated from a wild especies of brazilian "armadillo" (Dasypus novemcinctus). Three days after inoculation, blood was collected without anticoagulant; the same process was repeated at 72 hours intervals during eighteen days in both, control and experimental groups. Quantitative biochemical parameters were direct, indirect and total bilirubin, fatty acids and serum proteins. The experimental animals showed an increase of direct bilirubin three days after inoculation. Increases in indirect and total bilirubin were, also, observed after six days. Glucose, fatty acids and serum proteins decreased after the third day of inoculation. In conclusion, the increase in bilirubin levels could be due to acute hemolysis; hypoglycemia, hypolipidemia and hypoproteinemia that could be related to hepatic lesions and septicemia. All parameters returned to normal levels after fifteen days, in all animals tested