Age-related change in peripheral blood T-lymphocyte subpopulations and cytomegalovirus infection in the very old: the Swedish longitudinal OCTO immune study.

Results from the previous times (Times 1-3) of the Swedish longitudinal OCTO immune study indicated that a combination of high CD8 and low CD4 percentages and poor T-cell proliferation in PBL was associated with a higher 2-year mortality in a sample of very old Swedish individuals. The combination of immune parameters was closely related to an inverted CD4/CD8 ratio. In the present study at Time 4 (T4) results are reported from the final follow-up of this longitudinal study, 8 years after it was initiated in 1989. An additional goal at this time point was to examine the immune system alterations in the very old in relation to evidence of lymphocyte activation and cytomegalovirus antibody status. In the present study immune system changes were identified that suggest a loss of T-cell homeostasis, as reflected by a decrease in the number of CD4 cells and a very significant increase in the number of CD8 cells in individuals with an inverted CD4/CD8 ratio. When considered over the duration of the OCTO study the inversion occurred in a high percentage (32%) of the individuals included in the original sample and was associated with non-survival. At T4 the changes were apparent in a number of the T-cell subsets, but particularly in the CD8+CD28-and CD57+ subsets. T-cell activation was significantly associated with the inversion of the CD4/CD8 ratio. In this very old sample the subset alterations were associated with evidence of cytomegalovirus (CMV) infection.

Changes in CD8 and CD4 lymphocyte subsets, T cell proliferation responses and non-survival in the very old: the Swedish longitudinal OCTO-immune study.

Results from a previous longitudinal study indicated that a combination of high CD8 and low CD4 percentages and poor T cell proliferation in peripheral blood lymphocytes was associated with higher mortality in a subgroup of a sample of very old Swedish individuals. The present study examined whether those results could be confirmed at a subsequent 2-year time interval by investigating if additional individuals from the same original sample had developed the immune profile associated with higher mortality. Subgroups were formed by cluster analysis and similar to our previous results, this follow-up study identified a subgroup of subjects (n = 18) with an immune profile which again included high CD8, low CD4 percentages and poor mitogen response and was associated with higher mortality. Over the 2-year period 12 additional individuals: (1) Developed this immune profile; and (2) Could be identified by changes in their CD4:CD8 ratios which progressively decreased over the study period. These results confirm our original study and indicate that in this very old sample, over a subsequent 2 year period, additional individuals moved into the cluster at risk for higher mortality.

Reduction in animal numbers required for antisera production using the subcutaneous chamber technique in rabbits.

The purpose of this study was to determine if the subcutaneous chamber technique would reduce the number of rabbits required for antisera production by enabling serial use of individual animals for multiple antigens. Rabbits were assigned to immunization protocols against two antigens in series that involved combinations of chamber implantation, Freund's adjuvant and injection of antigen either by the subcutaneous route or by direct inoculation into the chamber. Results indicate the systemic immune response to both antigens achieved similar magnitude and duration by use of either Freund's adjuvant or direct inoculation of antigen into the chamber, suggesting that chamber use may be able to replace use of Complete Freund's adjuvant for many antigens. Rabbits re-used for a second antigen were equally successful in production of significant titres in both serum and chamber fluid without evidence of either a significant inflammatory response due to the chronic presence of the implant or a decrease in the yield of antisera harvested from the chamber. These results support the advantages of chamber use as reported by others and demonstrate that the chamber technique can significantly extend the productive life of an individual animal that would otherwise be euthanized following a single use in antisera production.

Immune parameters in a longitudinal study of a very old population of Swedish people: a comparison between survivors and nonsurvivors.

As a part of an ongoing longitudinal investigation, this study examined relationships between survival and selected immune system parameters in a sample (n = 102) of very old individuals (86-92 years at the time of initial immune system data collection). Analyses were performed comparing initial time-point measurements from those individuals who were alive (n = 75) and those who were deceased (n = 27) two years after initial data collection. Immune system measurements consisted of determination of peripheral blood lymphocytes and lymphocyte subsets, as well as T-cell responses to activation by Concanavalin A. Cluster analysis identified a subgroup associated with nonsurvival which indicated characteristics that included: poor T-cell proliferative responses, high CD8 percentages, and low CD4 and CD19 percentages. This multivariate analysis suggested that combinations of immune system parameters predict two-year survival otherwise not apparent when single immune system parameters were evaluated in the elderly.

Age-related differences in subset composition and activation responses of intestinal intraepithelial and mesenteric lymph node lymphocytes from neonatal swine.

Interesting differences were found in the phenotypes and functional responses of intestinal intraepithelial lymphocytes (IEL) and mesenteric lymph node lymphocytes (MLN) from neonatal swine aged 15 to 47 days. IEL and MLN differed significantly in their proliferative responses to the mitogens concanavalin A (Con A) and phorbol ester with ionophore (TPA/ionomycin) and to the cytokine, interleukin 2 (IL-2). IEL did not proliferate well in response to Con A, yet they were able to initiate a high proliferative response to exogenous IL-2, suggesting previous activation. In addition, the IEL response to TPA/ionomycin was very low unless the concentration of ionomycin was increased. With increasing age of the animals, response of the IEL increased. This IEL developmental response pattern was associated with a significant age-related change in T cell phenotype from CD2-4-8- cells to CD2+4-8- cells. In contrast to IEL, proliferation of MLN to Con A and TPA at a lower ionomycin concentration was significant and not influenced by age. Unlike the IEL, MLN were unresponsive to exogenous IL-2. Similar to IEL, they produced very little IL-2 in response to Con A stimulation. Both lymphoid tissues contained 70% T cells and in the MLN more cells were CD4+ or CD4+8+ and fewer were CD4-8- compared to the IEL. These differences between IEL and MLN in neonatal swine may reflect differences not only in the state of cell activation related to the in vivo microenvironment, but also the nature of responsive cell types in each lymphoid tissue.

Age- and strain-related differences in murine spleen cell responses to different activation signals.

The effect of age on the response of splenocytes to activation with anti-CD3 mAb and a combination of anti-CD3 mAb and TPA, as evidenced by interleukin-2 (IL-2) and interleukin-4 (IL-4) production and cell proliferation, was examined in the C57BL/6 and DBA/2 murine strains. Depending on the mode of activation, there were age and strain differences in IL-2 and IL-4 production. With all modes of activation, cells from the old C57BL/6 mice produced less IL-2 than their young counterparts. In DBA/2 mice there was no age-related difference in IL-2 production with anti-CD3 mAb activation alone, whereas when the same cell population was activated with anti-CD3 mAb and TPA an age-associated decrease in IL-2 production occurred. In both strains, there was an age-related increase in IL-4 production with anti-CD3 mAb activation. After addition of TPA, however, there was an age-related decrease in IL-4 production. An age-related decline in the proliferation occurred with all modes of activation in both mouse strains. There were also strain-related differences in proliferation after the addition of forskolin, an inhibitor of Th1-cell function. While forskolin inhibited the proliferation of cells from the young C57BL/6 mice only, in the DBA/2 mice proliferation of cells was inhibited in both age groups. There were no strain-related differences in inhibition by anti-transferrin receptor (TrfR) mAb, although cells from the old mice were slightly more sensitive to this inhibition.

The effect of selected arachidonic acid metabolites on natural killer cell activity.

The effect of arachidonic acid (AA) metabolites of lipoxygenase(s) was evaluated on natural killer (NK) cell activity in Fischer F344 rat splenic lymphocytes and compared with prostaglandin E2 (PGE2), a known inhibitor of NK cell lytic activity. It was observed that 5(S),12(S)-dihydroxy-6,10-trans-8,14-cis-eicosatetraenoic acid (5(S),12(S)-diHETE, EZEZ) inhibited NK cell activity to a degree comparable to the inhibitory effects of PGE2. This compound maximally inhibited NK cell activity at concentrations of 10(-6) and 10(-8) M. PGE2 and 5(S),12(S)-diHETE (EZEZ) inhibited NK activity to an identical degree at all concentrations and effector:target (E:T) cell ratios tested. Of the other lipoxygenase pathway metabolites screened, 8(S),15(S)-all trans-diHETE and 8(S),15(S)-diHETE (EZEZ) also inhibited NK activity, but only at 10(-6) M and a 50:1 E:T cell ratio. These findings provide further evidence that the lipoxygenase and cyclooxygenase pathways produce metabolites which can modulate NK cell function, and that 5(S),12(S)-diHETE (EZEZ), which has not been previously tested for effects on NK cells, may have a significant immunoregulatory role.

Activation of swine peripheral blood lymphocytes with human recombinant interleukin-2.

These studies examined the effect of the lymphokine interleukin-2 (IL-2) on porcine peripheral blood lymphocytes (PBL). Cultures of porcine (Yorkshire) PBL in human recombinant (r) IL-2 had a time-dependent increase in activation of killer cells. Previous reports of porcine killer cells derived from PBL indicated maximal lysis 18 hr after killer and target cells were mixed, with very little lytic activity at 4 hr. After culturing for 2 days in rIL-2, the cells acquire enhanced lytic capabilities resulting in substantial target lysis in the 4-hr assay. Enhanced lytic activity in the 18 hr assay occurs as early as 30 min after exposure to rIL-2, with a more significant increase after 2 days' exposure. The IL-2-treated cells have an increase in the incorporation of tritiated thymidine and an increase in percentage of granular cells. Tumour targets, such as Daudi, which are resistant to lysis, and L929, Mdt4 and P815, which are moderately susceptible to lysis by untreated swine PBL, had a substantial increase in lysis in IL-2-treated swine PBL. These results indicate human rIL-2 induces functional and morphological changes in swine peripheral blood lymphocytes.

Antibody-dependent cell-mediated cytotoxicity in pigs.

Development of antibody-dependent cell-mediated cytotoxicity (ADCC) was studied in cells obtained from porcine fetal and neonatal tissues. Pulmonary washouts, hepatic tissues, splenic tissues, and neutrophil fractions of blood were sources of cells. Neutrophils from fetuses and newborn pigs had high levels of ADCC activity, whereas the cells obtained from the other organs had highest activity shortly after the pig was born; in the case of pulmonary and hepatic cells, activity decreased by 84 hours following birth of the animal. The increased ADCC activity in tissues of pigs after birth appeared to coincide with increasing numbers of neutrophils in the various tissues.

Suppression of cellular immune responses by mouse amniotic fluid.

Mouse amniotic fluid (AF) strongly inhibited the in vitro generation of cell mediated cytolytic responses to allogeneic EL4 tumor cells. Potent immunoregulatory capabilities of AF in utero are suggested by in vitro suppression of immune responses by concentrations below physiological levels and by the inhibition of lytic function late in effector cell differentiation. Finally, suppression was not contingent on the parity of the female or the source of effector cells or of the AF.

Pregnancy and lactation induced suppression of cell mediated immunity.

The effect of pregnancy and lactation on effector or killer cell responses of syngeneically bred BALB/c (H-2d) female mice to the EL4 (H-2b) tumor and C57BL/6 (H-2b) female mice to the P815 (H-2d) tumor was evaluated with cell mediated cytolysis (CMC). Virgin age correlated females served as controls. Maternal spleen cell responses to the tumor were depressed at 10-15 days of pregnancy and during lactation at 1-5 days and 10-20 days postpartum. One to five days after weaning the maternal response began to increase again. In this study the greatest suppression of the response occurred at 1-5 days postpartum. The route of tumor sensitization, i.e. intraperitoneal or subcutaneous, did not make a difference in the depression of the maternal response. Serologic evaluation of splenic cell populations with anti-Thy 1.2 serum did not indicate differences which could account for the suppressed maternal CMC response.

An in vitro and in vivo analysis of murine immunocompetence during pregnancy and lactation.

Spleen cells from pregnant and lactating BALB/c mice were depressed in their cytolytic capabilities after in vivo immunization with the allogeneic EL4 lymphoma. However, in vitro spleen cells from both syngeneic (BALB/c X BALB/c) and allogeneic (BALB/c X C57BL/6J) matings responded with proliferative and cytolytic responses which were comparable to virgin controls. Upon secondary in vitro stimulation, in vivo primed maternal cells had responses which were similar to virgin controls. In addition, the in vivo sensitized maternal spleen cells adoptively immunized in irradiated allogeneic recipients responded like the virgin controls. In these studies, suppressor cells could not be detected in either nonimmune or immune maternal spleen cell populations.

Use of 51Cr-labeled mononuclear cells for measuring the cellular immune response in mouse lungs.

Spleen cells labeled with 51Cr were used in sensitized syngeneic mice to measure the degree of mononuclear cell infiltration into antigen-challenged tissues. With this method, increased cellular infiltration was found after footpad challenge of mice sensitized with sheep erythrocyte, Escherichia coli, and BCG antigens. Cellular response also was determined by using this technique in the lungs of mice sensitized with sheep erythrocytes and BCG. This procedure offers the opportunity to measure cellular infiltration, whether due to cellular or humoral influences, in tissues not easily accessible to conventional immunological manipulation.

Alterations in thymus and spleen cell populations and immune reactivity during syngeneic pregnancy and lactation.

Maternal thymus and spleen cell composition and mitogenic responsiveness were examined in the mouse during syngeneic pregnancy and lactation. The results indicated significant changes in thymus cell populations and in thymus cell in vitro mitogen, mixed-leukocyte and in vivo graft-versus-host (GVH) responses during pregnancy and lactation. In the spleen, in vitro mitogen responses were not altered, however, in vivo GVH reactivity was decreased during lactation.

Three variations of hairlessness associated with albinism in the laboratory rat.

The relationship of three variants of hairlessness, or hypotrichosis, in laboratory rats were examined morphologically, genetically and histologically. The results indicated that the recessive gene causing the fuzzy characteristic in Wistar Furth rats and genes responsible for two other hypotrichotic coat variants in albino rats were the same gene or closely linked genes. The genes were in Linkage Group I of the Norway rat and were closely associated with the albino gene (c), with a recombination percentage of approximately 18%. The hypotrichotic animals had fewer and smaller hair follicles, smaller hair shafts, and a reduction of medullated hair shafts.

Idiopathic megaesophagus in a rat (Rattus norvegicus).

Necropsy and histopathologic examination of a rat (Rattus norvegicus) revealed megaesophagus and gangrenous bronchopneumonia. The esophageal dilitation, mural atrophy with persistence of neural structures, regurgitation and bronchopneumonia seen in this case were similar to findings in other animals with megaesophagus.

Reactivity of rat placental cells with alloantisera.

The nature of the protection afforded the placental structure against the immunologic consequences that could result from maternal exposure to paternal alloantigens remains obscure. One problem has been difficulty in antigenically defining the individual cellular components of the intact placenta. These studies were designed to examine serologically, with specific antisera, five cell types isolated from the rat placenta. The results indicate that non-Ag-B antigens are present on the cytotrophoblast cells, while Ag-G antigens are absent on all the cells except an undefined population of fibroblasts. Of particular significance is the obvious absence of detectable surface antigens on the cells directly in contact with the maternal tissues, the trophoblast mononuclear giant cells.

Fuzzy, a hypotrichotic mutant in linkage group I of the Norway rat.

A new recessive hypotrichosis gene in the rat designated fuzzy (fz) is described. Fuzzy is linked to albino (c) in linkage group I with a 18.13 +/- 3.05 percent recombination. After an initial sparse hair coat, the fuzzy animals rapidly become devoid of hair. Histologically the skin of these animals has poorly developed, and often cystic hair follicles that contain accumulations of keratinacious material.