Avian delayed-type hypersensitivity: adaptation of the migration-inhibition assay

Ontogeny of delayed hypersensitivity in young turkeys

Hypersensitivity to phytohemagglutinin (PHA-P) and Freund's adjuvant containing Mycobacterium tuberculosis was investigated in turkey poults. The kinetics, as indicated by dosage and response time after sensitization, were similar to responses in other birds and laboratory mammals. Newly hatched poults demonstrated delayed hypersensitivity responses, and 2 week old poults exhibited responses of greater magnitude than 8 week old poults. The turkey is proposed as another acceptable species for study of cell-mediated immunity (CMI).

Inhibition of chicken leukocyte migration in vitro: a direct agarose plate assay

Leukocyte migration inhibition (LMI) is a widely used in vitro correlate of delayed type hypersensitivity (DTH) in mammals. This report describes the development of a direct agarose LMI assay for studying DTH in avian species. Optimum demonstration of LMI was found with leukocytes isolated on a Ficoll-diatrizoate gradient solution. The agarose culture plates were maintained at pH 7.2-7.4 in a water-vapor saturated, 39 degrees C. incubator with 2% CO2 tension. Antigen specific LMI was demonstrated in chickens with DTH to purified protein derivative of Mycobacterium (PPD) and ferritin. A good comparison between LMI and DTH, as measured by the delayed wattle reaction (DWR), was demonstrated. The effect of bacterial lipopolysaccharide (LPS) on LMI was examined and LPS in microgram quantities was found to inhibit in vitro migration of chicken leukocytes. Contamination of antigen preparations with LPS is a probable explanation for occasional nonspecific inhibition of leukocyte migration since endotoxin is an almost ubiquitous contaminant of antigen preparations.

Cellular and humoral anti-tumor immune responsiveness in chickens bearing tumors induced by avian sarcoma virus

A systematic comparison was undertaken of the respective abilities of normal chicken embryo fibroblast (CEF) cells, Rous sarcoma virus (RSV)- transformed CEF cells, avian Rous sarcoma (RS) tumor cells and murine RS cells to serve as targets and antigen donors in various assays for the detection of cellular and humoral anti-tumor immunity in chickens bearing tumors induced by Rous sarcoma virus. As measured by a cytotoxicity procedure, avian and murine RS cells were more susceptible to the killing effects of sensitized lymphocytes than were transformed CEF which in turn were more reactive than normal CEF. In contrast, sera from tumor-bearing animals were able to stain by indirect immunofluorescence only the avian RS and transformed CEF cell types. Extracts of both transformed CEF cells and avian RS cells but not normal CEF were equally effective as inhibitors of migration of peritoneal exudate cells derived from tumor-bearing animals. Transformed CEF were found to produce far higher quantities of transforming virus progeny than avian RS cells, although the latter were apparently albe to synthesize defective viral particles. These data indicate the significant variations which may occur under experimental conditions, depending on the types of assays and target cells employed.

The production of a lymphocyte inhibitory factor (LyIF) by bursal and thymic lymphocytes

In this study the migration and migration inhibition of different lymphoid cell populations from immunized and control birds were evaluated. Bursal, thymic, and splenic cells migrated in a capillary tube with thymic cells forming the characteristic cone of cells within 4 hours of culture. Both thymic and bursal cell populations from birds sensitized by Mycobacterium tuberculosis produced a lymphocyte inhibitory factor (LyIF) when stimulated by specific antigen in vitro. The ability of bursal cells to release LyIF declined subsequent to 10 weeks of age while LyIF was not apparent in thymic lymphocytes until 9 weeks of age and remained high until 27 weeks of age. The active material generated in specifically stimulated cultures from sensitized bursal cells appeared to be antigen dependent whereas thymic cell mediator is antigen independent. The production of LyIF in chickens, while correlating with delayed type hypersensitivity, does not solely reflect T-cell function but B-cell response as well.

Detection of cellular immunity to rous tumors of chickens by the leukocyte migration inhibition reaction

Peripheral blood leukocytes obtained from Rous sarcoma-bearing chickens were tested for their ability to be inhibited from migrating in vitro by soluble tumor extract. It was found that the inhibition of leukocytes from chickens with regressing Rous tumors was significantly greater than that of chickens with progressing tumors or non-tumor bearing controls.