Denis R. Burger

Endothelial cell presentation of antigen to human T cells.

Activation of human T cells requires presentation of antigen by Ia (HLA-DR in man) bearing cells of the mononuclear phagocytic series (macrophages, MO, and more recently Langerhans cells, dendritic cells, and vascular endothelial cells. Since T cells must cross endothelial barriers to enter extravascular tissues during immune reactions, we investigated the role of endothelial cells in antigen presentation. Endothelial cells were cultured from human umbilical veins and identified by classic morphology and specific markers (factor VIII related antigen, and so on). Antigen-pulsed endothelial cells were used to present antigen to MO-depleted human T cells; activation was assessed by 3H-thymidine uptake. The HLA-DR compatible endothelial cells were as effective as MO in reconstituting MO-depleted T-cell responses. The endothelial cell reconstituted responses were antigen specific, HLA-DR restricted, and blocked by monoclonal antibodies to HLA-DR framework structures. Moreover, the T-cell responses were clonal with respect to HLA-DR. A monoclonal antibody completely eliminated MO reconstitution of the MO-depleted response without diminution of endothelial cell reconstitution of the same response. Fibroblasts and smooth muscle cells cultured from the same umbilical veins could not reconstitute the MO-depleted T-cell response. These data indicate that endothelial cells play an important and distinctive role in lymphocyte triggering.

Transfer factor therapy in patients with cancer

The objective of this study was to utilize transfer factor to stimulate cell‐mediated immunity to specific tumor antigens in cancer patients. Thirty‐five selected patients with advanced recurrent cancer, who were not suitable for further conventional therapy, were treated with transfer factor. Transfer factor was prepared from cohabitants of the patients and administered at 2‐week intervals. This immunotherapeutic approach produced a clinical effect in 13 patients in terms of regression of tumor (1), arrest of metastatic disease (14), or pain relief (14). Conversion of dermal reactivity to specific tumor antigens was observed during periods of clinical improvement. Despite continued immuno‐therapy, the duration of clinical improvement was short (2 weeks to 12 months). Seven of the 11 patients not responding to therapy exhibited serum blocking of lymphocyte responsiveness. In 11 patients there is insufficient data to evaluate the clinical effectiveness of this therapy. The results suggest that transfer factor can stimulate specific cell‐mediated immunity in cancer patients and produce a clinical effect on tumor under certain circumstances.

Cell mediated immunity in experimental allergic encephalomyelitis: cross reactivity between myelin basic protein and mycobacteria antigens

Summary Guinea pigs injected with Freunds incomplete adjuvant emulsified with guinea pig spinal cord, purified guinea pig myelin basic protein, or human myelin basic protein showed dermal reactivity to both of the basic proteins as well as to myco-bacteria antigens. Animals receiving only mycobacteria antigens expressed dermal reactivity to the sensitizing antigen in addition to basic protein. This cross reactivity may help explain the role of mycobacteria in inducing and protecting against EAE, and may have important implications concerning human demyelinating diseases. We are grateful for the assistance of Hatsumi Park and Patricia Finke.

Transfer Factor from Guinea Pigs Sensitive to Dinitrochlorobenzene: Absence of Superantigen Properties

Transfer factor from guinea pigs sensitive to dinitrochlorobenzene was not bound to an immunoadsorbent column that is specific for the dinitrophenyl determinant. The absence of the dinitrophenyl determinant on transfer factor suggested that the factor does not function as superantigen. The duration of the adoptive sensitivity, the small molecular weight, and the polypeptide or polynucleotide (or a combination) composition of the transfer factor are consistent with a derepressor function of the molecule.

Changes in tumor immunity during therapy determined by leukocyte adherence inhibition and dermal testing

Leukocyte adherence inhibition (LAI) is an easily carried out in vitro test for tumor reactivity which is based on the prevention of adherence of leukocytes incubated with antigen to which the donor is immune. In this study a comparison is made with dermal response to tumor antigen. A total of 234 patients were tested, 74 of whom had melanoma, 111 of whom had squamous cell carcinoma of the head and neck, 18 of whom had neuroblastoma and 31 of whom had other tumors. Forty‐two persons without tumors acted as controls for the LAI test. A high degree of correlation was found between LAI and dermal response. Furthermore, LAI exhibited marked tumor specificity and showed a ten‐fold greater sensitivity than dermal response. LAI may be used to monitor serial changes in tumor reactivity in cancer patients.

Influence of serum blocking factors on cancer patients undergoing immunotherapy.

Blocking factors are small polypeptide molecules that may appear in the serum of patients with cancer. These factors block the transformation of lymphocytes in culture to nonspecific mitogens such as phytohemagglutinin or concanavalin A and, therefore, may reflect changes in the immunocompetence of the patient. Blocking factors were monitored during the clinical course of thirty-five patients with cancer. These factors did not develop in patients with response to therapy whereas they did develop in patients without response. A third group of patients without response to therapy after a previous remission showed an absence of lymphocyte responsiveness in culture that was not due to blocking factors, suggesting that immune clone consumption had occurred. Dermal responsiveness to tumor antigen correlated with a favorable clinical course and was usually absent when serum blocking factors were present.

Sensitization of human lymphocytes in vitro kinetics and specificity of the response to hemocyanins

In vitro primary sensitization of human peripheral blood T-cells to hemocyanins was detected during a 12-14 day culture period with antigen (KLH or HCH)-pulsed macrophages. Primed T-cells proliferate in secondary culture (2-3 days) when restimulated with antigen presented by macrophages. The kinetics of primary sensitization and secondary responsiveness are interrelated and are dependent on the antigen doses employed. Antigen-induced proliferation of cells sensitized in vitro is identical to proliferation of T-cells from immunized donors in terms of antigen specificity and the clonal nature of the response to antigen. Through the use of thymidine suicide techniques, distinct populations of cells responding to KLH or HCH can be demonstrated using cells from actively immunized donors or cells that have been sensitized in vitro to both hemocyanins.

A Model for Immunity to Melanomas in Mice

Summary C57BL mice immunized with cultured B16 melanoma cells developed both humoral and cellular immunity to melanoma antigens but were not resistant to melanoma cell challenge. Spleen, lymph node, and peritoneal exudative cells from immunized mice, however, passively transferred melanoma immunity to normal mice. Recipient mice were melanoma resistant if challenged with tumor cells 2 days, rather than 16 days, after adoptive transfer. Peritoneal exudative cells were more effective in the cell transfer experiments than the spleen or lymph node cells. Antimelanoma antibody was detected in unimmunized mice with large tumors and all immunized mice. In unimmunized mice antimelanoma antibody appeared to be associated with progressive tumor growth.

Improved lymphocyte serotyping techniques for organ matching

Lymphocyte isolation and serotyping techniques are described which are rapid, simple, and reliable. Two methods of microcytotoxicity testing are discussed with variations to accommodate different clincial and laboratory circumstances. A cytotoxic 51Cr release method is described. The results obtained from all methods correlated exactly with established microcytotoxicity methods. The phase-microscopy method may be performed within the time requirements for cadaveric matching and is suitable for use with uremic patients with lymphopenia.