Category Archives: Lymphocytes

Characterization of Lymphocytes in the Adult Rat Testis by Flow Cytometry: DISCUSSION(5)

DISCUSSION(5)

In conclusion, it appears that the majority of the T cells in the testis interstitium are composed of the CD8+ largely cytotoxic MHC class I-restricted T-cell subset and that, conversely, the CD4+ MHC class II-restricted T-cell subset exists in greatly reduced numbers as compared to those in blood. This finding supports the observations of prolonged allograft survival within the rat testis, which led to the testis’ being considered an immunologically privileged tissue. The reduced proportion of CD4+ T cells in the testis would correlate with a reduced capacity for initiating antigen-specific cellular and humoral immune responses, thus reducing the risk of development of unwanted immune reactions to developing autoantigenic germ cells and grafts. buy ortho tri-cyclen

Characterization of Lymphocytes in the Adult Rat Testis by Flow Cytometry: DISCUSSION(4)

The fact that activin, like TGFfS, effectively suppressed the proliferation of PHA-stimulated blood T cells, without any selective effect on either T-cell subset, does not support our hypothesis that activin or TGF(3 could be responsible for regulating the differential proportions of the individual T-cell subsets within the rat testis. However, the possibility of other subset-specific actions of these cytokines that do not involve proliferative responses cannot be excluded. The data do confirm that CD4+ and CD8+ peripheral T cells are inhibited by activin to a similar extent. The fact that inhibin exhibited no effect on PHA-stimulated peripheral blood T-cell proliferation suggests that the action of inhibin on thymocyte proliferation in vitro may be due to a selective effect on immature T-cell development. Alternatively, while it seems unlikely that inhibin stimulates the growth of other thymic cells, since inhibin exerts a significant effect on proliferation only in the presence of a T-cell mitogen such as PHA, this does not exclude the possibility that inhibin may stimulate thymocyte growth though actions on a non-lymphocytic cell type present in the thymus but not in peripheral blood. ventolin inhalers

Characterization of Lymphocytes in the Adult Rat Testis by Flow Cytometry: DISCUSSION(3)

 DISCUSSION(3)

In the blood, the number of cells labeled with OX19 was equivalent to the number labeled by R73, as expected. In the testis, however, the 0X19 labeling of T cells was consistently less than labeling for R73+ cells. Previous studies have demonstrated that T-cell expression of CD5, the antigen recognized by 0X19, is extremely low particularly on cytotoxic T cells and is developmentally regulated. It appears that there may be a minor population of T cells in the adult rat testis that either expresses levels of CD5 that were undetectable or may even lack CD5. Although the functional importance of this observation is unknown, similar “CD5-negative” T cells have been observed in blood from human immunodeficiency virus-infected patients; and it was proposed that these were a “transitional” population between the T-cell and NK cell lineages. In any event, the 0X19 data suggest that 76 T cells, which are also CD5+, do not represent a significant population in the rat testis. The very low proportion of T cells labeled with OX-22 in the rat testis is consistent with the previous immunohistochemical study indicating that most, if not all, of the testicular T cells are antigen-primed or memory T cells. buy ampicillin

Characterization of Lymphocytes in the Adult Rat Testis by Flow Cytometry: DISCUSSION(2)

The percentage of isolated blood lymphocytes that expressed the NK cell receptor in the present study (3.0%) was similar in magnitude to the percentage of NK cells in peripheral rat blood that has been reported previously. From the results obtained in the present study, moreover, it is clear that NK cells are a major lymphocyte subpopulation within the rat testis, essentially composing approximately 30% of the overall lymphocyte population. This is a substantially higher proportion than that observed in blood. These data also indicate that the very low level of OX8 expression on NK cells in the testes detectable by flow cytometry was insufficient to be detected by the im-munohistochemical procedures employed in the previous study. buy levaquin online

Characterization of Lymphocytes in the Adult Rat Testis by Flow Cytometry: DISCUSSION(1)

DISCUSSION(1)

This study confirms the predominance of the CD8+ T-cell subset in the adult rat testis and demonstrates that a substantial population of NK cells also are present. This suggests that, while it is an immunologically privileged site for grafts, the rat testis remains capable of effective virus and tumor surveillance.

The data obtained for CD4 and CD8 T-cell subset proportions in the blood were consistent with our data using immunohistochemical techniques, which demonstrated that the testicular T-cell population of the adult rat was biased toward the CD8 subset. The CD4:CD8 T-cell ratio obtained in this present study confirms this bias with use of a more direct approach and indicates that within the testicular interstitial tissue of the rat there are at least 2.5 times more CD8+ T cells than CD4+ T cells. This is very different from the proportion in blood, where CD4+ T cells predominate. ventolin inhaler

Characterization of Lymphocytes in the Adult Rat Testis by Flow Cytometry: RESULTS(4)

In the blood, 70.6% of isolated leukocytes were сф T cells (R73+), 8.3% were В cells’ (OX33+), and 3.0% were NK cells (high-intensity 3.2.3-labeled) (Fig. 5). The remaining leukocytes may be attributed to the presence of monocytes and some neutrophils. Of the total T-cell number, an average of approximately 17% were CD8+ T cells and the remaining T cells (83%) can be assumed to be CD4+; this was consistent with the high level of W3/25-labeled cells in the blood (which would include both the CD4+ T cells and some monocytes).

In the testis, 60.7% of the isolated leukocytes were a(B T cells and 25.4% were NK cells. The small number of testicular leukocytes that were unaccounted for may be attributed to residual monocyte/macrophage contamination after the isolation procedure, since granulocytes are not present in the normal rat testis. Of the testicular T cells, approximately 64% were CD8+ T cells, and the remaining T cells (36%) can be assumed to be CD4+, consistent with the low level of W3/25 labeling in the testis (which includes both the CD4+ T cells and possibly some residual monocyte/macrophages).

Characterization of Lymphocytes in the Adult Rat Testis by Flow Cytometry: RESULTS(3)

 RESULTS(3)

Comparison between blood and testis of the mean labeling of cells by particular mAbs, expressed as a percentage of total leukocytes (OX1+ cells), is shown in Figure 5. Similar results were obtained for both Dark Agouti rats (4 experiments) and Sprague-Dawley rats (2 experiments), although only data for the former are presented. Note that antibody 0X8 is represented as high intensity-labeled cells (i.e., T cells that express high levels of CD8) and total labeled cells (i.e., both T cells and NK cells that exhibit much lower variable levels of CD8). Similarly, antibody 3.2.3 is represented as high intensity-labeled cells (i.e., NK cells that express the NK receptor) and total labeled cells (i.e., both NK cells and some T cells expressing low levels of the NK cell receptor). buy diabetes drugs

Characterization of Lymphocytes in the Adult Rat Testis by Flow Cytometry: RESULTS(2)

On the basis of these results, it was determined that fraction II (1.089-1.071 g/ml) provided optimal yield and purity of T cells, and this fraction was used for lymphocyte proliferation assays. For the cell-labeling studies, however, in order to maximize lymphocyte numbers, fractions II and III were combined (1.053-1.086 g/ml). levitra super active plus

Immunofluorescent Analysis of Blood and Testis Leukocytes

The number of leukocytes (OXl+ cells) recovered from 5 ml of peripheral blood following Percoll fractionation was 16.2 ± 1.4 X 106 cells (mean ± SD, n = 3 experiments). In the same experiments, the total number of cells recovered from one testis following fractionation and the adherence step was 1.2 ± 0.5 X 106 testicular cells, of which 41.2 ± 7.4% (mean ± SD) were leukocytes (OXl+).

Characterization of Lymphocytes in the Adult Rat Testis by Flow Cytometry: RESULTS(1)

RESULTS(1)

Distribution of Immune Cells on Percoll Gradient

In preliminary studies, blood cells were fractionated on several discontinuous Percoll density gradient types: 1) 1.095-1.083-1.077-1.059 g/ml, 2) 1.095-1.086-1.0741.059 g/ml, and 3) 1.095-1.089-1.071-1.059 g/ml, with the majority of mononuclear cells eluting at densities > 1.059 g/ml (Fig. 1). Fractions containing relatively pure mononuclear cells (90-97%) were obtained at the gradient step interfaces between Percoll densities 1.089 and 1.071 g/ml (Fig. 1 and Fig. 2A). This fraction (fraction II) contained an average total mononuclear cell recovery of 33%, 45%, and 60%, respectively, for the three gradient types. Gradient fractions above 1.089 g/ml displayed increased numbers of granulocytes (predominantly neutrophils with small numbers of eosinophils) and erythrocytes. Buy Asthma Inhalers Online

Characterization of Lymphocytes in the Adult Rat Testis by Flow Cytometry: MATERIALS AND METHODS(6)

From the cells within the detection gate, the fluores-cence-intensity distribution was determined for each antibody. For each individual mAb used, the percentage of cells positively labeled within the detection gate was determined, and the total numbers of each cell type were calculated by application of the labeling percentages to the total numbers of cells recovered during isolation.

Histology

Isolated cells were smeared, fixed in methanol, and stained using May-Grunwald (3 min, 20°C) and Giemsa (5 min, 20°C) stains. Cells were identified and counted using an Olympus (Tokyo, Japan) microscope with X100 oil-im-mersion objective.

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