Localization of alpha-fetoprotein in human and rat fetal livers. An immunohistochemical method using horseradish peroxidase

α-Fetoprotein (AFP) was successfully demonstrated in paraffin-embedded sections of human and rat fetal livers, by a multilayering immunohistochemical technique using the peroxidase-antiperoxidase system. Serial sections simultaneously subjected to immunofluorescence showed identical sites of localization in hepatocytic cytoplasm and sometimes in perivenous connective tissue. AFP-containing hepatocytes were located around efferent veins as well as randomly in the lobule. The immunoperoxidase technique has certain advantages over the immunofluorescence method which would justify the former's application in studies on the dynamics of AFP synthesis.

Lymphopoiesis in protein deficiency. Stathmokinetic and tritiated thymidine uptake studies of the mesenteric lymph node of the guinea pig

In view of the depressed immunity in protein malnutrition, an assessment of the lymphoproliferative activity of the constantly stimulated mesenteric lymph node of the guinea pig was undertaken. A significant reduction of this activity was observed in protein deficiency. a) The germinal centers were reduced in number and size; new formation in the medulla was rarely seen. Lymphoid cells showed lowering of mitotic index and mitotic rate and prolongation of mitotic duration and turnover time. Nuclear labeling with (3)H-thymidine was focal and localized to the peripheral zone. b) Mitotic activity and nuclear labeling were less pronounced in the outer cortex and medulla and least in the paracortical area. Specific uptake of (3)H-thymidine paralleled the low labeling index. c) No appreciable reduction in the number of plasma cells in the medulla was observed. Serum gamma-globulin levels were not significantly altered, but albumin levels were consistently reduced. This was suggestive of preferential preservation of plasma cell activity in the malnourished host. d) There were significant lymphopenia and neutropenia with relative increase of neutrophils in the peripheral blood. This might indicate more severe involvement of lymphopoiesis than myelopoiesis in protein malnutrition.

Immune responses of the protein-deficient guinea pig to BCG vaccination

Two groups of guinea pigs were maintained on high-protein and low-protein diets and immunized with intradermal BCG. Protein deficiency was accompanied by marked inhibition of local and systemic immune responses: a) The BCG nodule was poorly formed. There was marked delay and deficiency in the mobilization of macrophages. b) The draining lymph node was atrophic and showed little or no proliferation of lymphoid cells in the paracortical area. Macrophage accumulation occurred late but became diffuse and marked, in contrast to its consistent scarcity in the BCG nodule. c) In either location epithelioid cell transformation was retarded. Well-formed mature epithelioid cell granulomas were not seen. d) Bacilli persisted for a long time in the skin and lymph node lesions, e) Tuberculin sensitivity was greatly impaired in one-fifth of animals and absent in others. These findings were suggestive of macrophage dysfunction and depression of cell-mediated immunity to BCG in the protein-deficient guinea pig.

Responses of the protein-deficient rabbit to staphylococcal bacteremia

Staphylococcal bacteremia was induced in two groups of rabbits that were pairfed high protein and protein deficient diets. Marked deviations in response were observed as a result of protein deficiency: a) blood clearance of S aureus was delayed; b) persistence and multiplication of bacteria in blood and tissues were pronounced; c) neutrophilic response was poor and transitory; d) mortality was very high and occurred very early and e) focal necrotizing lesions, rather than well-formed abscesses, were found in organs.