Biomedical subjects

G F Erf

Publications and source records attributed to G F Erf.

41 records · Page 3Linked to original sources

PubMed1993

Immune development in young-adult C.RF-hyt mice is affected by congenital and maternal hypothyroidism.

C.RF-hyt mice carry a mutation (hyt) that results in the phenotypic expression of congenital hypothyroidism in hyt/hyt mice due to a nonresponsiveness of the thyroid gland to thyroid-stimulating hormone. Heterozygotes of this strain are euthyroid. To further define thyroid-immune interactions, the effect of congenital hypothyroidism and maternal hypothyroidism on immune development were examined in 3- to 4-month-old hyt/+ and hyt/hyt progeny from hyt/+ and hyt/hyt dams. The state of immune development in these mice was compared on the basis of immune organ weights and the proliferation response of splenocytes stimulated with the T cell mitogens concanavalin A (Con A) and phytohemagglutinin and the B cell mitogen lipopolysaccharide. In addition, analysis of T cell subpopulations in thymus and spleen was conducted using direct and indirect immunofluorescence and flow cytometry. Data analyses for the main effects of congenital hypothyroidism on immune development revealed a significantly lower absolute thymus weight (P < 0.001), a lower (P = 0.022) percentage of thymocytes expressing CD8 (CD8+), a higher (P = 0.010) ratio between CD4+ and CD8+ thymocytes, a lower (P < 0.001) absolute and adjusted spleen weight, a lower (P = 0.001) Con A to phytohemagglutinin response ratio, a higher (P = 0.003) percentage of CD4+ splenocytes, and a marginally significant (P = 0.055) increase in the ratio between CD4+ and CD8+ splenocytes in hypothyroid compared with euthyroid mice. Data analyses for the main effects of maternal hypothyroidism revealed a significantly higher absolute (P = 0.025) and adjusted (P = 0.001) thymus weight, a higher (P = 0.006) ratio between CD4+ and CD8+ thymocytes, a lower Con A (P = 0.018) and lipopolysaccharides (P < 0.001) response, a marginally (P = 0.069) lower Con A to phytohemagglutinin response ratio, a lower (P = 0.001) percentage of CD4+ splenocytes, and a lower (P = 0.003) ratio between CD4+ and CD8+ splenocytes in progeny of hypothyroid compared with progeny of euthyroid mothers. These data provide further evidence for the importance of normal thyroid function in the development, maintenance, and function of the immune system. It was concluded that not only congenital hypothyroidism results in altered immune development in young-adult mice, but also long-term effects on immune development occur in progeny of hypothyroid mothers.

Animals↗

PubMed1989

Effect of dietary triiodothyronine on mixed-lymphocyte responsiveness in young male chickens.

The effect of dietary triiodothyronine (T3) supplementation (0, 0.1, 0.1, and 1.0 ppm of T3) on the mixed lymphocyte response (MLR) was examined in MHC-matched young Cornell K and sex-linked dwarf (SLD) strain cockerels at ages 6, 9, and 12 weeks. At all ages, MLR in SLD strain cockerels was significantly lower than in the K strain. Supplementation of 6-week-old cockerels with 0.01 and 0.1 ppm of T3 tended to decrease MLR in both strains, whereas the highest dose of T3 had the opposite effect in the K strain and no effect in the SLD strain compared to the control. No significant effects of T3 on MLR were observed in 9-week-old cockerels. A significant main treatment effect of T3 on MLR was observed in 12-week-old cockerels. At this age dietary T3 decreased MLR in both strains. These results show that allo-aggression, a functional parameter of cell-mediated immunity, can be affected by non-MHC controlled strain differences and by the iodothyronine state of these strains.

Animals↗

PubMed1988

Triiodothyronine affects the phytohemagglutinin to concanavalin A proliferative response ratio in sex-linked dwarf chickens.

Euthyroid Cornell K strain and sex-linked dwarf (SLD) strain cockerels (which have abnormally low serum triiodothyronine concentrations) were supplemented with either 0, 0.01, 0.1, or 1.0 ppm of triiodothyronine (T3) in the diet. Peripheral blood lymphocytes (PBL) from these cockerels were obtained by slow-speed centrifugation (slow-spin-prepared PBL). The proliferative response of these PBL to phytohemagglutinin (PHA) and concanavalin A (Con A) was determined when the chicks were 6, 9, and 12 weeks of age. Con A responsiveness was also determined in 12-week-old cockerels using PBL which were separated on Ficoll (Ficoll-prepared PBL). Using slow-spin-prepared PBL, PHA, and Con A responsiveness increased in both strains with increasing levels of T3 supplementation. This enhancing effect of T3 was particularly evident in older cockerels. In 6- and 12-week-old SLD strain cockerels, the PHA:Con A response ratio was significantly (P less than 0.05) lower than in K strain cockerels. At 12 weeks of age the PHA:Con A response ratio of the SLD strain was elevated to K strain control levels by T3 supplementation. Therefore, the lower PHA:Con A response ratio in the SLD strain appears to be partially due to the existing peripheral hypothyroidism in this strain. Using Ficoll-prepared PBL, the effects of T3 on Con A responsiveness differed from those observed when slow-spin-prepared PBL were used. From this study we conclude that T3 supplementation affects mitogen responsiveness and the PHA:Con A response ratio. However, the effects of T3 on mitogen responsiveness depend on the age of the chicken, the level of T3 supplemented, the T cell population stimulated, and the method of lymphocyte enrichment.

Aging↗

PubMed1987

Graft-versus-host response in sex-linked dwarf, autosomal dwarf and control K strain chickens.

Two independent experiments were conducted to examine the ability of 1) the autosomal-dwarf (ADW) strain and 2) the sex-linked (SLD) strain chicken to make a Graft-versus-Host (GvH) response. In each experiment the GvH response of the dwarf strain was compared to the GvH response of a normal growing control strain, the Cornell K strain chicken. All 3 strains were homozygous B15/B15 at the major histocompatibility complex. GvH responsiveness of peripheral blood lymphocytes (PBL) from females of each strain was assessed at various intervals from 1.5 to 20 months of age using the chorio-allantoic membrane (CAM) assay. The GvH response in female chickens from the ADW strain was significantly higher than in K strain females after the birds had reached sexual maturity (after 5.5 months). The GvH response in females from the SLD strain was, however, significantly lower than in the K strain females throughout the experiment. All strains tended to have a biphasic GvH response. There was a significant increase in GvH responsiveness from 1.5 to 5.5 months of age in chicks from all strains. In the SLD and K strain chickens, this was followed by a drop in the GvH response until 8.5 months of age. In 16- to 20-month-old SLD and K strain hens, the ability to mount a GvH response returned to levels observed in younger (5.5 months) pullets. The GvH responsiveness of the ADW strain remained at a constant level from 5.5 to 12 months of age. However, a second peak in GvH responsiveness was observed in 16-month-old ADW strain hens. Strain differences in GvH responsiveness may be due to the known hormonal abnormalities in the dwarf strains. The suitability of these dwarf strains for the study of endocrine-immune interrelationships is discussed.

Animals↗

PubMed1987

Triiodothyronine affects mitogen responsiveness in sex-linked dwarf and Cornell K strain chickens.

The response of lymphocytes to concanavalin A (Con A) was examined in the functionally hypothyroid SLD strain and the normal K strain chickens which were fed diets with or without T3 supplementation (0.1, 0.5 and 1.0 ppm) since the time of hatch. Peripheral blood lymphocytes (PBL) from 3 and 12 week old male and female chickens were incubated with Con A for 60 h. Mitogenic responsiveness was assessed by measuring the uptake of 3H-thymidine during the last 24 h of incubation. There was no difference in the mitogen response between male and female chickens. The mitogen responsiveness of PBL from the K strain tended to be greater than that from the SLD strain at both ages. The lowest dose of T3 (0.1 ppm) had no effect on the mitogen response of 3-week-old K strain chicks but caused an increase in mitogen response in 3-week-old SLD and in 12-week-old birds of both strains. Supplementation with 0.5 and 1.0 ppm T3 tended to decrease mitogen responsiveness in the K and SLD strain at both ages. The effect of treatment on thymus weights, bursa weights, and lymphocyte concentrations of the blood was also assessed.

Animals↗