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D D Eckels

Publications and source records attributed to D D Eckels.

70 records · Page 4Linked to original sources
PubMed1982

Antigen-specific human T lymphocyte clones: mechanisms of inhibition of proliferative responses by xenoantiserum to human nonpolymorphic HLA-DR antigens.

We studied the effects of xenoantiserum to human nonpolymorphic Ia-like antigens upon in vitro antigen-specific T cell proliferative responses in unfractionated PBL populations and at the monoclonal level. Our findings suggest that the xenoantiserum, although it inhibits the antigen-specific response of unfractionated PBL and allospecific T cell clones, does not inhibit the proliferative response to cloned influenza virus immune human T lymphocytes, and therefore may be mediating inhibition by dual mechanisms: direct inhibition of alloantigen recognition and induction of nonspecific suppression. Kinetic differences may explain these phenomena. In cocultivation experiments with a virus-specific clone, the RaIa antiserum appears to induce an OKT3+,8+,4-, radiosensitive regulatory subset of lymphocytes. When adoptively transferred, these induced cells inhibit the TLC response in an antigen-nonspecific and genetically nonrestricted manner. We discuss the various modes and levels of inhibition of antigen-specific proliferation by anti-Ia antisera and their multiple activities.

Clone Cells↗
PubMed1982

In vitro influenza virus-specific antibody production in man: antigen-specific and HLA-restricted induction of helper activity mediated by cloned human T lymphocytes.

Cloned human T lymphocytes induced with influenza A virus (A/Texas/1/77) and maintained in continuous culture with T cell growth factor were assayed for helper function in the in vitro production of anti-influenza antibody. Helper function mediated by both cloned helper T cells and normal peripheral blood lymphocytes was highly antigen dose-dependent, requiring lower concentrations than that necessary to induce blastogenesis. Optimal help was observed with 1 X 10(2) cloned T cells per culture, whereas excess helper cells inhibited the response. After culture with influenza A virus-induced cloned helper T cells, the antibodies formed were directed against influenza A and not B virus. Furthermore, the cloned helper T cells despite being specific for matrix protein collaborated in the production of predominantly anti-hemagglutinin antibody, suggesting associative recognition of the two discrete antigens. Cellular interactions between cloned helper cells from an HLA-Dw1,3 DR1,3 individual and erythrocyte rosette-negative cells required HLA-Dw1; DR1 compatibility for the production of specific antibody. This was confirmed by using subclones. Finally, it was observed that supernatants of the cloned helper T cells contained functional activity capable of replacing the parent cells in the production of anti-influenza A virus antibody.

Antibodies, Viral↗
PubMed1981

Pharmacologic and biochemical modulation of human T-lymphocyte colony formation: hormonal influences.

The generation of T-cell colonies from human peripheral blood lymphocytes is a sensitive in vitro measure of cell-mediated immunity, considered to be under different and/or additional regulatory controls than short-term liquid cultures. The influences of steroids (aldosterone, estradiol, diethylstilbestrol, hydrocortisone, prednisolone, progesterone, testosterone), prostaglandins (PGA1, PGA2, PGB1, PGB2, PGE1, PGE2, PGF1 alpha), bradykinin, cyclic adenosine monophosphate (AMP), cyclic guanosine monophosphate (GMP), epinephrine, glucagon, histamine, insulin, luteinizing hormone, luteotropic hormone, serotonin, and thyroxin on the generation of both T-cell colonies in semisolid phase and induction of transformation in liquid culture was assessed in parallel assays. Steroids uniformly suppressed both types of culture systems, although colony formation appeared more sensitive by several hours of magnitude. In contrast, significant differences in the response of lymphocytes in colony formation assay, compared to liquid transformation, was noted for the other agents. Prostaglandins significantly inhibited colony formation even in the presence of as little as 10(-12) M PGE2; however, liquid culture responses were suppressed only by higher concentrations (10(-5) M) and enhanced transformation was found at lower concentrations (10(-9) M). Bradykinin, glucagon, and luteinizing hormone did not significantly influence either colony formation or liquid transformation. In contrast, cyclic AMP inhibited and cyclic GMP stimulated colony formation and liquid transformation. Histamine, insulin, epinephrine, and serotonin all had significant positive or negative influences on colony formation in concentrations that produced no detectable effects using conventional liquid transformation assays. Finally, correlation analysis of drug effects for each system extends the thesis that these assays quantitate different parameters of T-cell function. T-lymphocyte colony formation is a promising diagnostic tool for rapid screening of immune modulating agents.

Colony-Forming Units Assay↗
PubMed1981

Monoclonal and xenoantibodies specific for HLA-DR inhibit primary responses to HLA-D but fail to inhibit secondary proliferative (PLT) responses to allogeneic cells.

Monoclonal antibodies (DA-2 and CA-2) and xenoantisera (rabbit anti-human, p23,30) specific for HLA-DR framework determinants were added to primary and secondary mixed lymphocyte cultures. Although such antisera were shown to inhibit primary MLC, primed lymphocytes were much less sensitive to the blocking effects of these antibodies. In the studies shown here, the concentration of antibody required to inhibit primary MLC reactions was 0.1-1.5 micrograms/ml).

Animals↗
PubMed1981

Evidence for a new HLA-region determinant detected by human T-lymphocyte clones (TLCs).

Human peripheral blood T-lymphocytes were stimulated by allogeneic cells in primary MLC and subsequently cloned by limiting dilution in the presence of lymphocyte conditioned medium (LyCM). Following expansion, clones were tested for specific proliferation against a panel of 32 stimulator cells including cells from the family of the original stimulator (FLAM). Two clones, TLC 14-14 and TLC 14-86, responded to FLAM and to a cell homozygous for Dw5 (JPSU), but not to other unrelated panel members; reactivity segregated with the haplotype containing Dw1 in FLAM's family. In separate experiments, TLC 14-14 was restimulated by an antigen encoded by the maternal "c" haplotype in JPSU's family. This antigen may be a new determinant on the same molecule as Dw1 and 5 or, more likely, encoded by a new gene associated with these specificities.

Clone Cells↗
PubMed1981

Depression of colony formation by human thymus-derived lymphocytes with rifampin and other antimicrobial agents.

Colonies of human lymphocytes with thymus-derived (T) cell characteristics can be induced in phytohemagglutinin-P to grow in a semisolid medium. To expand the data base on the effects of antimicrobial agents on cell-mediated immunity, the effect of 30 antimicrobial agents on T-lymphocyte cloning was studied. All of the drugs were added to the cultures in concentrations ranging from 10(-5) to 10(-14) M, and the results were compared with those in cultures without the drug. Drugs that inhibit protein synthesis at the 50S ribosomal subunit in bacteria--in particular, chloramphenicol, clindamycin, erythromycin, and troleandomycin--suppressed colony formation. However, the most significantly immunosuppressive agent was rifampin; it suppressed colony formation at concentrations of up to 2.5 x 10(-9) M, a value significantly lower than that found in previous in vitro testing and well below therapeutic levels. Screening of drugs by lymphocyte cloning techniques for possible suppression of cell-mediated immunity appears to be a rapid, sensitive, and inexpensive procedure.

Adult↗
PubMed1979

The influence of dietary protein concentration and energy intake on mitogen response and tumor growth in melanoma-bearing mice.

The effects of energy deprivation and low or high dietary protein levels upon lymphocyte transformation of spleen cells from syngeneic tumor-bearing and control mice were studied in a murine model of malignant melanoma. Both T- and B-lymphocyte transformation were significantly stimulated by the presence of a growing melanoma. T-cell responses however, were dependent only upon dietary protein concentrations, not the level of energy intake; whereas, the converse was true for B cells. Moreover, mice fed stock diet had the lowest response to mitogens of all diets tested. Except for mice receiving a 15% casein diet, tumor weights were generally not affected by level of intake or the amount of dietary protein. Others have demonstrated that melanoma cells have a greater need for tyrosine or phenylalanine than other tumor cells; thus we hypothesized that lymphocyte transformation may be depressed by relatively low phenylalanine or tyrosine levels in the diet when protein intakes are limited by either a low dietary concentration a restricted intake of a diet containing adequate protein, or both.

Animals↗
PubMed1979

Comparative patterns of serum immunoglobulin levels in specific-pathogen-free congenitally athymic (nude), hereditarily asplenic (Dh/+), congenitally athymic-asplenic (lasat) and splenectomized athymic mice.

Serial determinations of serum immunoglobulin levels were assessed in congenitally athymic (nude), hereditarily asplenic (Dh/+) and congenitally athymic-asplenic (lasat) mice and the results compared to normal intact littermate controls (nu/+), neonatally splenectomized nu/+ and neonatally splenectomized nude mice. Quantification of Ig levels was accomplished by radial immunodiffusion, for IgM, IgG1, IgG2a, IgG2b and IgA antibody isotypes. Intact spleen and/or thymus function was shown to have marked effects on the age-dependent development of serum IgM, IgG2b and IgA production. Furthermore, because of higher levels of IgA in congenitally athymic-asplenic mice and neonatally splenectomized nude mice v. sham splenectomized nude mice, it is suggested that an IgA-specific suppressor population resides in the spleen. Finally, because of frequent problems in the literature in interpretation of immunoglobulin values, the criteria for the statistical evaluation of such data in establishing normal serum Ig values and ascertaining real differences between treatment groups are emphasized.

Aging↗
PubMed1979

Therapeutic manipulation of Nb rat prostatic adenocarcinomas: chemotherapeutic evaluation of autonomous tumors.

Nb rat autonomous prostatic adenocarcinomas were transplanted into several groups of synergeneic Nb rats. Chemotherapy using 5-fluorouracil, methotrexate, Adriamycin, and cyclophosphamide was evaluated. Significance was seen with the use of these agents with varying doses. Cyclophosphamide and 5-fluorouracil treated animals had complete tumor regression whereas Adriamycin and methotrexate treated animals had cessation of tumor volume increase in some groups after chemotherapy; however, neither agent causes complete tumor regression.

Adenocarcinoma↗
PubMedDate not supplied

Restoration of alloreactivity of melanoma by transduction with B7.1.

Melanoma cells are unusual because, unlike most epithelial tumors, constitutive expression of human leukocyte antigen (HLA) class II molecules is common. To elucidate the role of HLA class II expression in the immunopathogenesis of melanoma, the authors compared HLA class II+ melanoma cells to autologous B cells with respect to their ability to stimulate primary (naïve) histoincompatible lymphocytes and T-cell clones (antigen experienced). Using primary lymphocytes (peripheral blood lymphocytes [PBLs]), melanoma cells were nonstimulatory when compared to autologous B cells. To determine whether this was caused by defective antigen processing, the authors used alloreactive T-cell clones, which require alloantigen presentation by a histocompatible stimulator cell but not costimulation. Melanoma cells stimulated the alloreactive T-cell clones in two of three clones tested, indicating that they processed and presented alloantigen. To determine whether the failure of melanoma cells to stimulate primary lymphocytes was caused by their inability to costimulate the T cells, the authors transduced the melanoma cells with B7.1 and achieved stable expression in more than 95% of the cells. The transduced cells were highly stimulatory, eliciting a 17- to 25-fold increase in proliferation by the peripheral blood lymphocytes compared with controls. Indeed, B7-expressing melanoma cells were more stimulatory than autologous B cells, which elicited an 11- to 15-fold increase compared with controls. These data indicate that melanoma cells fail to stimulate primary lymphocytes because they do not deliver costimulatory signals. Engineering HLA class II+ melanoma cells to express high levels of B7.1 may provide a way to elicit primary T-cell responses to melanoma-associated antigens.

Antibodies, Monoclonal↗
PubMedDate not supplied

T lymphocyte colony formation and autoimmune disease: in vitro assessment of immunopathology.

Human T lymphocyte colonies were generated with phytohemagglutinin in semi-solid media to assess the influence of cellular and humoral components upon colony formation by patients with systemic lupus erythematosus (SLE) compared to normal age-matched controls. Optimal colony formation occurred for patients with SLE and controls approximately 6 d after culture. However, colony formation by patients with active disease was significantly reduced compared to both controls and patients with inactive disease. Similar results were obtained in liquid cultures. There was no statistical correlation between colony forming capacity and quantitation of liquid culture transformation. Observation of the influences of patient sera produced striking dose response relationships. SLE sera were found to inhibit colony formation at high concentration (30-190%) but enhanced at lower concentrations (25-694%).

Autoimmune Diseases↗