Biomedical subjects

R A Good

Publications and source records attributed to R A Good.

At least 19 recordsLinked to original sources

PubMed1992

Human prolactin regulates transfected MMTV LTR-directed gene expression in a human breast-carcinoma cell line through synergistic interaction with steroid hormones.

Prolactin plays a key role in the regulation and growth of mammary cells, and influences tumor promotion. We have shown that chronic energy restriction intake depresses prolactin levels, inhibits production of MMTV proviral DNA and proto-oncogene expression in mammary glands and prevents development of mammary tumors. Since the expression and proto-oncogene activation of MMTV are regulated by promoter/enhancer elements within its long terminal repeat (LTR), in the present study we used a chloramphenicol acetyl transferase (CAT) reporter gene system and gene transfection methods to study the effect of prolactin on MMTV LTR using a human ductal carcinoma cell line T47D stably or transiently transfected with a plasmid consisting of the LTR upstream of CAT gene. Human prolactin or dexamethasone induced, respectively, a 2-fold or 6-fold increase in CAT activity compared with background CAT activity in the absence of hormones. However, the combination of human prolactin and dexamethasone strongly enhanced (20-fold) induction of the LTR compared with the control. Human prolactin also showed a synergistic effect with progesterone on LTR induction. Both LTR and CAT genes needed to be linked for induction of CAT activity by prolactin and dexamethasone. Our results indicate that human prolactin can act synergistically with steroid hormones to regulate MMTV LTR-directed gene expression in transfected T47D cells.

Breast Neoplasms↗

PubMed1992

A strategy for making synthetic peptide vaccines.

We have determined the H-2 class II allele-specific amino acid motif of the agretope (the site of contact between the peptide antigen and the major histocompatibility complex) for a synthetic peptide composed of residues 43-58 of pigeon cytochrome c (p43-58). Residues 46 and 54 functioned as the agretope, and residues 50 and 52 functioned as the epitope (the site for contact between the peptide antigen and the T-cell antigen receptor). In general, agretopes and epitopes function independently. Thus, substitution of amino acids in the epitope does not significantly affect binding of the peptide antigen to a class II molecule. On the basis of these findings, synthetic peptide vaccines against influenza Aichi (H3N2) virus were prepared by introducing seven residues of the influenza virus hemagglutinin into the frame component residues 43-46 and 54-58 of p43-58 analogues including the agretopes for Ak or Ab previously determined on the p43-58 segment. These peptide vaccines induced both helper T-cell responses and production of antibodies that were specific for influenza Aichi hemagglutinin but not for the major histocompatibility complex binding frame in mice bearing Ak or Ab. The antibodies produced neutralize the infectivity of influenza Aichi in vitro. The present findings should provide a basis for preparing potent peptide vaccines that function without producing side effects.

Alleles↗

PubMed1992

Superantigen staphylococcal enterotoxin B-induced T-helper cell activation is independent of CD4 molecules and phosphatidylinositol hydrolysis.

The role of the CD4 molecule in activation of T-helper cells was examined by investigating the effect of an anti-CD4 monoclonal antibody (Leu3a) in conventional peptide antigen-specific cloned T-helper cells that are also reactive to staphylococcal enterotoxin B (SEB). These T-helper cell clones are CD4+/CD45RO+/T-cell antigen receptor beta-chain variable region 12-positive and can respond to nominal peptide antigens and SEB by proliferation in the presence of class II major histocompatibility complex-expressing accessory cells. Although antigen and SEB were comparable in their ability to induce proliferative responses, interleukin 2 (IL-2) production, and IL-2 receptor alpha-chain expression, stimulation with SEB failed to trigger phosphatidylinositol hydrolysis or a rise in the intracellular free calcium ion concentration. Leu3a treatment inhibited antigen-induced proliferative responses of T cells with concomitant suppression of IL-2 production and IL-2 receptor expression. In contrast, SEB-induced responses were unaffected by Leu3a. These findings indicate that the functional consequences of binding (ligation) of conventional antigen and of superantigen with the T-cell receptor are distinct in the context of both signal transduction pathways and participation of CD4 molecules.

Antibodies, Monoclonal↗

PubMed1992

An NK1.1+ CD4+8- single-positive thymocyte subpopulation that expresses a highly skewed T-cell antigen receptor V beta family.

In the present report we describe a CD4+8- heat stable antigen-negative (HSA-) thymocyte subpopulation that expresses a distinguishably low density of alpha beta T-cell antigen receptors (TCRlo) from the majority of CD4+8- high-density TCR (TCRhi) mature-type thymocytes. This subpopulation appears relatively late in life. Analysis of MEL-14, Pgp-1 (CD44), ICAM-1 (CD54), and NK1.1 expression on this subpopulation revealed that the CD4+8- TCRlo population was a population having unique characteristics (MEL-14-, CD44+, ICAM-1+, and NK1.1+) compared to the CD4+8- TCRhi thymocytes, most of which are MEL-14+, CD44-, ICAM-1-, and NK1.1-. When TCR beta-chain variable region (V beta) usage was analyzed, this thymic population expressed predominantly products of V beta 7 and V beta 8.2 TCR gene families. Interestingly, cells with V beta 8.1 TCRs, which are reactive to Mls-1a antigens, were not eliminated from the CD4+8- HSA- TCRlo subpopulation but had been eliminated from the major CD4+8- HSA- TCRhi subpopulation in Mls-1a strains. A subset with a phenotype similar to the CD4+8- HSA- TCRlo thymocytes was also identified primarily in bone marrow, and this subset constituted approximately half of the CD4+ T cells in the bone marrow. The CD4+8- HSA- TCRlo cells showed extremely high proliferative responses to immobilized anti-TCR antibody but generated negligible responses to allogeneic H-2 antigens compared to the responses generated by the major CD4+8- HSA- CD3hi cells. However, the CD4+8- HSA- TCRlo cells in Mls-1b mice mounted vigorous proliferative responses to Mls-1a antigens but not in Mls-1a mice. The properties of this T-cell subset suggest that these cells belong to a lineage distinct from the major T-cell population.

Age Factors↗

PubMed1992

Improved enzyme immunosorbent assay for mouse prolactin using penicillinase as label.

Enzyme immunosorbent assay (EIA) for mouse prolactin was established by modifying a method originally developed for human prolactin by Shrivastav et al. This simple, sensitive, rapid, and reproducible assay utilizes penicillinase as the labeling enzyme, rabbit anti-mouse prolactin antibody (Ab) and goat anti-rabbit Ig Ab as the first and second antibodies. Prolactin reference preparations and enzyme-conjugated prolactin were mixed with the first Ab and incubated for 0.5 h at 4 degrees C (24-48 h for serum samples). Then, the sample mixture was transferred to the wells of microtiter plate coated with the second Ab. After being kept at room temperature for 2 h, the plate was washed and filled with substrate solution (penicillin V). Absorbance at 620 nm was measured with an ELISA reader to quantitate the amount of conjugated prolactin bound to the second Ab. The prolactin levels obtained by this assay exhibited good correlation with those measured by radioimmunoassay (RIA) (y = 0.95x + 9.14, r = 0.943), and the sensitivity of EIA was equivalent to that of RIA (1.7 ng/ml). The CVs of intra-assay and inter-assay by EIA for mouse serum samples ranged comparably to those by RIA.

Aminoquinolines↗

PubMed1992

Influence of calorie restriction on oncogene expression and DNA synthesis during liver regeneration.

Controlling calorie intake (CCI) extends healthful life-span by a mechanism that may involve reduced rates of cell division without detriment to inducible cellular responses. To test whether inducible cellular proliferation is preserved by CCI and whether the mRNA expression levels of oncogenes activated by cell division can be reduced by CCI, we evaluated the effect of dietary energy on the hepatocellular proliferative burst and on oncogene and growth factor mRNA expression induced by partial hepatectomy. Eighty Fischer 344 rats were separated into two dietary groups and were fed semipurified diets for 10 weeks that differed only in calories by 40%. Mean hepatic levels of [3H]thymidine incorporation were greater among CCI animals at 18, 24, 28, and 36 hr after partial hepatectomy. The expression of c-fos and c-Ki-ras mRNAs, activated during hepatic regeneration, was reduced by CCI. Peak expression of c-fos among ad libitum fed controls to levels 4-6 times greater than prehepatectomy levels was not detected among CCI animals. Protracted elevated expression of c-Ki-ras among ad libitum fed animals was foreshortened by CCI. These findings demonstrate that inducible cellular proliferative responses are preserved by CCI and that the mRNA expression levels of c-fos and c-Ki-ras activated during cell division are reduced by controlling dietary energy. Preserved inducible cellular responses and lowered oncogene expression during cell division may be attributes of the healthful protective effect of CCI.

Animals↗

PubMed1992

The effects of dietary restriction on immune function and development of autoimmune disease in BXSB mice.

Chronic energy intake restriction (CEIR) prolonged the median life span and inhibited autoimmunity and development of autoimmune disease in BXSB mice, as has been established for mice of several other autoimmune-prone, short-lived strains. Whether imposed just after weaning or delayed until manifestations of disease had appeared, CEIR inhibited or reversed development of autoimmunity and immune complex-based renal disease in male BXSB mice. CEIR also prevented the formation of anti-DNA antibodies and prevented the increase in circulating immune complex levels that is typically observed in male mice of this strain. Moreover, CEIR inhibited development of splenomegaly and prevented the normal age-associated decline of a number of immunological functions, including interleukin 2 production, cell-mediated cytotoxic responses, and mixed lymphocyte reactivity. The observed improvement in cell-mediated immune responses was attributed largely to the capacity of CEIR to inhibit development of the splenomegaly that occurs concomitant with expansion of a non-T, non-B lymphoid cell population. These findings emphasize that CEIR, even when imposed relatively late in life in BXSB mice, can influence expression of autoimmunities and autoimmune diseases of different genetic origins and presumed pathogenetic bases.

Age Factors↗

PubMed1992

Induction of heat shock protein closely correlates with protection against Toxoplasma gondii infection.

Heat shock proteins (HSPs) are evolutionarily highly conserved polypeptides that appear to be produced by many cells to preserve cellular functions under a variety of conditions of stress, including infections. We report that a 65-kDa HSP is present in mouse peritoneal cells that have been infected with a low-virulence (Beverley) strain of Toxoplasma gondii, as determined by electroblot assay using a monoclonal antibody specific for microbial HSP65. This HSP is, however, not expressed when infection occurs with the high-virulence RH strain of T. gondii. Furthermore, HSP was demonstrable in mice that acquired resistance against infection with a lethal dose of bradyzoites of the Beverley strain or even of an inoculum of a highly virulent strain of T. gondii (RH). From these results, it can be suggested that HSPs play an important role in developing effective defenses that include effective immune responses against infection with Toxoplasma parasites in vivo.

Animals↗

PubMed1992

A synthetic peptide homologous to retroviral envelope protein down-regulates TNF-alpha and IFN-gamma mRNA expression.

We investigated the influence of CKS-17, a synthetic heptadecapeptide that corresponds to a highly conserved domain of the immunosuppressive retroviral envelope protein p15E, on staphylococcal enterotoxin B (SEB)-induced TNF-alpha gene expression in human peripheral blood mononuclear cells and highly purified human monocyte preparations, as well as the production of TNF-alpha protein, using human peripheral blood mononuclear cells. RNA hybridization studies show that CKS-17 inhibits SEB-induced TNF-alpha mRNA accumulation in human peripheral blood mononuclear cells and human monocytes. CKS-17 is also shown to be highly suppressive for SEB-induced production of TNF-alpha proteins. Similarly, CKS-17 inhibits expression of SEB-induced IFN-gamma mRNA in human peripheral blood mononuclear cells. These results suggest that CKS-17 down-regulates both TNF-alpha and IFN-gamma production at mRNA level.

Amino Acid Sequence↗

PubMed1992

Suppression of human interferon-gamma production by a 17 amino acid peptide homologous to the transmembrane envelope protein of retroviruses: evidence for a primary role played by monocytes.

CKS-17, a synthetic amino acid peptide homologous to a highly conserved region of retroviral transmembrane protein exerts a suppressive action on staphylococcal enterotoxin A (SEA)-induced the production of IFN-gamma by human peripheral blood mononuclear cells (PBMC) (Ogasawara et al., J. Immunol. 141, 615, 1988). This action has been shown in the present study to be preceded by dramatic clustering of PBMC. Clusters appear within 3 hr of exposure of PBMC to CKS-17; they are dose dependent, inhibited by cycloheximide, and require a temperature of 37 degrees C. The cells in the clusters are predominantly monocytes. Although it has been previously shown that CKS-17 inhibits monocyte-mediated killing by inactivating IL-1 (Kleinerman et al., J. Immunol. 139, 2329, 1987) and production of IL-2 by murine thymoma cells treated with IL-1 (Gottlieb et al., J. Immunol. 142, 4321, 1989), in the present study we show that IL-1 does not prevent clustering of PBMC by CKS-17. Using CKS-17 and highly purified monocytes or lymphocytes, profound alterations occur only with monocytes, as revealed by light or electron microscopy. SEA- or staphylococcal enterotoxin B-induced production of IFN-gamma is inhibited when highly purified monocytes pretreated with CKS-17 are cocultured with highly purified T lymphocytes. Thus, CKS-17 induces dramatic clustering of cells apparently by inducing alterations of monocytes but not lymphocytes, suggesting that CKS-17 may interfere with the capacity of monocytes to facilitate production of IFN-gamma by T lymphocytes.

Amino Acid Sequence↗

PubMed1992

Effects of K-76COOH (MX-1) on immune response: induction of suppressor T-cells by MX-1.

K-76COOH (MX-1), isolated from the cultured supernatant of a species of fungi imperfecti, Stachybotrys complement nov. sp. K-76, is an inhibitor of the complement component, C5. The effects of MX-1 on various immune responses were investigated. MX-1 enhanced the response of spleen cells to PHA and LPS: MX-1 at 0.01-250 micrograms/ml for PHA and at 10-250 micrograms/ml for LPS. In contrast, it inhibited the response to Con A: MX-1 at 0.01-500 micrograms/ml for spleen cells and at 100-500 micrograms/ml for thymocytes. MX-1 and IL-1 synergistically acted to enhance the Con A response of spleen and thymus cells from which accessory cells and Ia-positive cells had been removed by passing through Sephadex G-10 columns and treating with anti-Ia monoclonal antibody plus complement. T-cells pretreated with MX-1, IL-1 and Con A for 3 days suppressed not only the response of B-cells to LPS but also the production of anti-SRBC antibodies. In addition, MX-1 was found to increase CD8+ T-cells. These results suggest that MX-1 acts on T-cells to induce suppressor T-cells.

Animals↗

PubMed1992

Nutrition and cellular immunity.

We have investigated the influence of nutrition on immune function in animals and man over the past two decades. The profound impairment of immune function that had not been observed in children in developing countries could not consistently be reproduced in the laboratory setting; paradoxically, moderate nutritional restriction could even enhance T-cell-based cell-mediated immune responses in experimental animals. Studies of the crucial role of the element zinc in maintenance of vigorous cellular immunity provided at least a partial explanation of this paradox. Zinc, shown to be absolutely crucial for development and expression of both T- and B-cell functions, was commonly deficient as were other micronutrients under many conditions of protein-calorie malnutrition. Indeed, administration of adequate zinc alone could correct some of the T-cell-mediated immune functions in children with protein-calorie malnutrition. In later investigations we found that as long as all essential nutrients were supplied in adequate amounts, 40% chronic energy (calorie) restriction will regularly extend lifespan and maintain vigorous immunologic function while preventing numerous cancers and immunologically based diseases of aging, such as profound and destructive autoimmune diseases in genetically short-lived mice strains, as it was known to do for moderately long-lived rats and long-lived strains of mice. Such undernutrition without malnutrition appears to influence a wide range of critical metabolic and physiologic processes in both short-lived and long-lived animals. One of the most challenging of these influences was a down-regulation of cellular proliferation and cell turnover in each of the rapidly replicating tissues studied.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

Ethanol calories do not enhance breast cancer in isocalorically fed C3H/Ou mice.

Mammary tumorigenesis is augmented when C3H/Ou mice are fed diet ad libitum but delayed when calories are restricted by 40%. Three feeding experiments were done to evaluate the effect of ethanol on mammary tumorigenesis in isocalorically fed C3H/Ou mice: 1) ad libitum feeding of semipurified solid diet, with one group receiving 12% ethanol (15 g/kg/day) in the drinking water while controls received water alone; 2) isocaloric pair feeding of semipurified solid diet, with ethanol (4 g/kg/day) administered by gavage five time per week; and 3) isocaloric pair feeding of Lieber-DeCarli liquid diet, with one group receiving 29% of calories as ethanol (20 g/kg/day) in the diet. Despite administration of ethanol to isocalorically fed C3H/Ou mice for 65 weeks by three different methods, mammary tumor development was not enhanced. In two of the three ethanol-consuming groups, weight gain and mean body weight were less in the ethanol-consuming mice than in the controls, despite equal total calorie consumption. In only one ethanol-consuming group, where mice received ethanol as a 12% solution in the drinking water, was any difference noted in the tendency to develop mammary tumors. In this case, delay in tumorigenesis was apparent in the ethanol-consuming animals (p = 0.03). These findings do not support the hypothesis that ethanol calories augment the risk of breast tumorigenesis among breast cancer-prone mice consuming isocaloric diets. Instead, reductions in weight gain and body weight among ethanol-consuming mice and an apparent reduction in mammary tumorigenesis in one of three experimental groups suggest that ethanol may decrease metabolic utilization of calories and hence contribute to lowered energy availability.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

Clonal elimination of self reactive V beta 6+ T cells induced by H-2 products expressed on thymic radio-resistant components.

The role of thymic radio-resistant cells on clonal elimination of V beta 6+ T cells that are reactive to minor lymphocyte stimulatory (Mls)-1a plus I-E antigens has been investigated. Previous studies with allogeneic bone marrow chimeras revealed that radio-sensitive I-E+ cells derived from donor bone marrow in the thymus play a major role in the clonal elimination of V beta 6+ T cells. However, we could show that not only the thymic bone marrow derived components but also the radio-resistant ones (presumably thymic epithelial cells) might be involved in induction of clonal elimination of the self-reactive T cells. The proportion of V beta 6+ T cells present varied with the H-2 haplotype of the thymus and the cell types presenting Mls-1a products, which might be attributable to differences in the affinity of the H-2 products to T cell antigen receptors and differences in the amount of tolerogens expressed on the stromal cells.

Animals↗

PubMed1992

Development and characterization of monoclonal antibodies to lymphocyte cell surface antigens of the rhesus monkey.

Three monoclonal antibodies directed against rhesus lymphocyte cell surface antigens are described. A pan-T mAb, T64, and a T suppressor mAb, T35, showed phenotypic and functional specificity for both human and rhesus cells. In contrast, a third mAb, N42, identifying natural killer cells in rhesus peripheral blood leukocytes, was not crossreactive with the corresponding homologous human cells. N42 reacted with the same cells identified by Leu 11a and Leu 11b in rhesus PBL and in a functional assay decreased NK activity by 80%. N42 precipitated a 50KD protein from rhesus PBL lysates and was reactive with the Fc receptor domain of the NK cell. The T-S functional activity of cells reactive with mAb T35 was demonstrated in a pokeweed-mitogen-driven system for Ig synthesis: removal of the T35 positive cells by complement-mediated lysis led to an enhanced production of Ig by rhesus PBL, and the addition of T35 positive cells to a culture of T helper and B cells resulted in a reduction of this response. T35 was determined to be an IgG2a immunoglobulin and precipitated a 34KD protein from rhesus cell lysates. An IgM immunoglobulin, mAb T64 delineated all T lymphocytes, inhibited E-rosette formation, interfered with the proliferation of cells stimulated with mitogens, and precipitated a 52KD membrane protein. The potential utilization of these mAbs in vivo for organ or tissue transplantation in the rhesus monkey is discussed.

Animals↗

PubMed1992

Functional evaluation of T helper, T suppressor, and B lymphocytes in lethally irradiated rhesus monkeys injected with autologous bone marrow.

Lethally irradiated rhesus monkeys were treated with autologous bone marrow that had either been (1) nontreated, i.e., normal; (2) depleted of T lymphocytes with a monoclonal antibody directed against rhesus T lymphocytes; (3) fractionated with the soybean agglutinin (SBA- fraction); or (4) fractionated with SBA and further depleted of T cells by E-rosetting. There was no difference in hematologic reconstitution among the animals, but all showed a marked lowering of the T helper/T suppressor ratio during the first 10 months posttransplant and reduced capability of their peripheral blood leukocytes (PBL) to produce Ig upon stimulation with pokeweed mitogen. This subnormal ability of PBL to produce Ig, as measured by plaque-forming cells in a reverse hemolytic plaque assay, was not explained entirely by the altered T-H/T-S ratio but was correlated with the functional status of the T-H, T-S, and B lymphocytes. Isolated populations of the different lymphocyte subsets from PBL of the experimental animals were cocultured with normal cells of the appropriate subset to obtain Ig synthesis when stimulated with PWM. Animals treated with normal bone marrow showed recovery of T-H cell function after 5 months, but their T-S cells showed excessive suppressor activity that persisted for 20 months posttransplant. In contrast, those animals receiving treated marrow (mAb plus complement, or SBA) showed a much-delayed (12 months or more) return to normal T-H cell function and an earlier return of T-S cells expressing a normal level of suppressor activity. Since the SBA- fraction of marrow contains very few or no T-H cells and T cell depletion of marrow with mAb also removes these cells, it is suggested that the kinetics of immune recovery of the different lymphocyte subsets of PBL is influenced by the presence or absence of T-H cells in the marrow inocula.

Animals↗

PubMed1992

RNA/nucleotide enhances antibody production in vitro and is moderately mitogenic to murine spleen lymphocytes.

Suppression of immune functions was demonstrated in both humans and animals when exogenous RNA was eliminated from the diet. However, direct actions of RNA/nucleotide on the immune system are virtually unknown. Thus, in this study, we explored effects of RNA and nucleotide on lymphocyte functions in vitro. Yeast whole RNA, which is free of endotoxin, was supplemented to culture media, and changes in mitogen responses, thymocyte proliferation, or in vitro antibody production by murine spleen lymphocytes were analyzed. Yeast whole RNA potentiated the proliferation of spleen lymphocytes and it also strikingly enhanced in vitro antibody production in response to sheep red blood cells at least 10-fold. However, it did not potentiate the proliferation of thymocytes (immature lymphocytes). These enhancing activities of yeast RNA were significantly reduced by RNAse treatment, but not by treatments with DNAse or polymyxin B. Certain mononucleotides exhibited less, but similar, action on murine spleen lymphocytes. The whole yeast RNA employed was already degraded to small nucleotide (less than 1 kb). Therefore, it may be suggested that certain components of RNA degraders can function as powerful immunomodulators, indicating that exogenous RNA or nucleotide may be important in facilitating immune responses under certain circumstances.

Animals↗

PubMed1992

Effects of calorie restriction on immunologic functions and development of autoimmune disease in NZB mice.

Chronic energy (calorie) intake restriction (CEIR) prolonged life, inhibited autoimmune disease, and influenced immunologic and hematologic parameters in NZB mice. Abnormalities in numbers and proportions of T and B cells populations were corrected. Deficient responses to phytomitogens, mixed lymphocyte reactions, formation of plaque-forming cells to sheep red blood cells in vitro, production of cytotoxic T lymphocytes after in vitro stimulation, and interleukin 2 production were also corrected. CEIR prevented the extreme splenomegaly that normally occurs with age in NZB mice. This influence was associated with reduction of a greatly expanded non-T, non-B lymphoid cell population. Calorie restriction also prevented in NZB mice the rapid decrease in total numbers of colony-forming B cells in bone marrow that is also characteristic of mice of this strain. The influences of CEIR on immune parameters and hematopoiesis were generally less marked in non-autoimmune-prone DBA/2 mice than in autoimmune-prone NZB mice. CEIR has been shown to produce profound influences on several strains of autoimmune-prone mice (NZB x NZW)F1, MRL/lpr, BXSB, and NZB herein). In each of these strains, the pathogenesis and manifestations of autoimmune disease are dissimilar. Therefore, it seems likely that calorie restriction acts on an as yet elusive mechanism that operates to foster development of the diseases associated with aging common to each of these autoimmune strains as well as autoimmune-resistant mice and rats. Further investigation of the molecular and cellular bases of the benefits of CEIR seems urgent.

Animals↗