Cytogenesis of thymus in prenatal buffalo (Bubalus Bubalis)

In thymus lymphopoiesis began at 60 mm CRL embryo (55 days) of buffalo. The lymphocytic precurssors developed in yolk sac or in bone marrow and they migrated to the thymus via circulation. At 60 mm CRL (55 days) stage thymic primordium contained two distinct populations of cells viz., lymphoblasts and epithelial reticular cells. The lymphoblast were highly basophilic and spherical in shape, whereas epithelial reticular cells characterized by less basophilic cytoplasm and stellate in shape. At 63 mm CRL (57 days of gestation) many lymphoblast showed mitotic divisions and by 65 mm CRL (58 days of gestation) functional small, medium and large lymphocytes were formed in thymus. At 63mm CRL (57 days) erythropoiesis began in parenchyma and stroma. At 65 mm CRL (58 days) extra vascular erythrocytes were found. Granulopoiesis in thymus began at 63 mm CRL, by 88 mm CRL neutrophils, eosinophils were noted.