Processing fate of protein antigen attached to IgD or MHC molecules on normal B lymphocytes using heterocrosslinked bispecific antibodies.

We have studied the internalization, processing and presentation of hen egg lysozyme (HEL) attached to surface IgD (sIgD) or MHC molecules on normal murine B cells, using heterocrosslinked bispecific antibodies (HBA). Nearly all HEL attached to sIgD was internalized within one hour, with at least a portion rapidly entering a chloroquine-sensitive, acidic environment. Degradation and presentation of HEL to hybridoma T cells began several hours after internalization.

T cell receptor-negative thymocytes from SCID mice can be induced to enter the CD4/CD8 differentiation pathway.

In order to investigate the role of T cell receptor (TcR) expression in thymocyte maturation, we have analyzed thymocytes from C.B-17/SCID mice, which are unable to productively rearrange their antigen receptor genes and fail to express TcR. Despite this defect, SCID thymocytes are functional as they produce lymphokines and proliferate in response to a variety of stimuli.

Effect of combined therapy with lymphokine-activated killer cells, interleukin 2 and specific monoclonal antibody on established B16 melanoma lung metastases.

We have previously shown that treatment of C57BL/6 mice with specific anti-B16 melanoma monoclonal antibody (Mab) significantly reduced the number of established liver metastases. In this paper we show that when treatment with Mab was applied to mice bearing both liver and lung micrometastases, the number of liver metastases was reduced by 72-98%, whereas no effect was seen on the number of lung metastases. In contrast to results obtained when treating liver metastases, treatment of B16 melanoma lung metastases with Mab and recombinant interleukin 2 was unsuccessful when recombinant interleukin 2 was given concomitantly or after priming with high doses of recombinant interleukin 2.

Engagement of the CD4 molecule influences cell surface expression of the T-cell receptor on thymocytes.

The intrathymic differentiation process by which precursor cells derived from the bone marrow develop into immuno-competent T lymphocytes is poorly understood. Most thymocytes express both CD4 and CD8 accessory molecules, yet little is known about either the function of these molecules or the responsiveness of the CD4+8+ double positive thymocytes that bear them. Here, we address the possibility that CD4 engagement influences T-cell receptor (TCR) expression on developing thymocytes.

Anti-tumor reactivity of human lymphokine activated killer (LAK) cells against fresh and cultured preparations of renal cell cancer.

Immunotherapy utilizing the adoptive transfer of lymphokine activated killer (LAK) cells in conjunction with recombinant interleukin-2 (IL-2) is capable of mediating the regression of established cancer in a variety of animal tumor models as well as advanced metastatic cancers in humans. We have thus examined the variability of the anti-tumor lytic reactivity of LAK cells obtained from patients with metastatic renal cell cancer (RCC). Tumor cell suspensions were prepared by enzymatic digestion from 37 consecutive renal cell tumors.