In vitro induction of tumor-specific immunity. VI: analysis of specificity of immune response by cellular competitive inhibition: limitations and advantages of the technique.

The cellular competitive inhibition 51Cr-release assay makes two distinct contributions to the in vitro study of cell-mediated immunity. It allows target cells which are not amenable to isotopic labelling to be investigated for their antigenic specificity, and it provides a means, complementary to the direct cytotoxicity assay, of estimating qualitative and quantitative differences in antigen expression on intact normal and neoplastic cells. Various parameters of a micro-51Cr-release inhibition assay have been studied, and it was found that the assay conditions markedly influenced both the sensitivity and specificity.

Cutaneous manifestations of disseminated cryptococcosis.

Five patients with disseminated cryptococcosis had lesions on the extremities resembling cellulitis, which evolved into areas of blistering and ulceration in three patients. All had underlying disease and were medically immunosuppressed. Disseminated cryptococcosis appears to present with cellulitis or herpes-like vesiculation more commonly than is currently appreciated.

Analysis of murine oncofetal antigens as tumor-associated transplantation antigens.

In previous studies with in vitro activated cytotoxic T lymphocytes, we have demonstrated the presence of oncofetal antigens (OFA) on a range of murine tumor cells. The present studies with the same tumor lines attempt to determine whether these antigens are also capable of activating lymphocyte responses in vivo. Several experimental designs were followed, each being performed many times (1).

In vitro induction of tumor-specific immunity. II. Activation of cytotoxic lymphocytes to murine oncofetal antigens.

The presence of oncofetal antigens (OFA) on a wide variety of murine tumor cells was demonstrated to a totally in vitro system of cellular immunity. Nonimmune spleen lymphocytes were cocultivated with irradiated syngeneic fetal liver cells and, at various times after initiation of culture, were tested for the presence of cytotoxic lymphocytes (CL) by 51Cr-release assay with labeled tumor target cells. Significant cytotoxic activity was regularly detected after such culture, whereas only minor levels appeared in control cultures of spleen lymphocytes with irradiated syngeneic spleen cells.

Genetic polymorphism of IgD-like cell surface immunoglobulin in the mouse.

Lymphocyte surface antigens from spleen cells of several mouse strains were studied by cell surface radioiodination, extraction with detergent incubation with various antisera, and separation of complexes using protein A-containing staphylococci as a solid phase adsorbent. Complexes were then dissociated and analyzed by polyacrylamide gel electrophoresis in the presence of sodium diodecyl sulfate. Using this technique and an alloantiserum prepared in C57BL mice against CBA spleen cells, four distinct specific peaks of radioactivity were found with CBA spleen cells.

Growth of B-lymphocyte colonies in vitro.

In semisolid agar cultures containing mercaptoethanol, cells from the spleen, lymph nodes, marrow, peritoneal cavity, thoracic duct, and blood of normal mice generated clusters and colonies of up to 3,000 cells. Colony numbers and growth were markedly enhanced by the addition of sheep red cells. The frequency of colony-forming cells in the spleen or lymph nodes was 0.

A subpopulation of T cells bearing Fc receptors.

A wide range of cell populations were examined for Fc receptor (FcR)-bearing T cells: thymus, spleen, peritoneal cells, and T cells activated to H-2 antigens in spleen (ATC spleen) and in thoracic duct lymph (T-TDL). In addition, B lymphocytes from thoracic duct lymph of athymic nude mice and a Thy-1-positive, FcR-positive thymoma served as control cell populations. Reagents used were aggregates of human gamma-globulin and of various mouse myeloma proteins (IgG1, IgG2a, IgG2b), radioiodinated antigen-antibody complexes, and sheep erythrocyte antibody rosettes.

Transplantation behavior of A.TH and A.TL T-cell lymphomas in congenic resistant and hybrid strains.

Seven spontaneously arising T-cell lymphomas originating in A.TH or A.TL mice, which are congenic for the immune response gene (I) chromosomal segment were described.

Radiosensitivity of T and B lymphocytes. III. Effect of radiation on immunoglobulin production by B cells.

Radiation injury in defined populations of B cells was investigated utilizing an allotype congenic transfer system. The amount of donor immunoglobulin present in the recipient's serum was found to be directly proportional to the number of viable cells injected, and on this basis approximate D37 values for the inoculated B cells were determined in several experiments and found to fall in the 70 to 145 rad range depending upon the specific experimental conditions. Since the sensitivity of T cells to radiation-induced interphase death can be modified by prior exposure to select mitogens and antigens, an attempt was made to demonstrate a similar phenomenon with respect to B cells.

In vitro induction of tumour-specific immunity. I. Development of optimal conditions for induction and assay of cytotoxic lymphocytes.

A microculture system for in vitro induction of tumour-specific immunity with syngeneic spleen cells and plasma-cell tumours is described. The system generates cytoxic lymphocytes assessed by their ability to lyse 51Cr-labelled target cells in a microcytotoxicity assay. Both the inductive and effector phases are subject to many variables in material and methodology and the optimal conditions are defined in this study.