Biomedical subjects

K B Gorden

Publications and source records attributed to K B Gorden.

3 recordsLinked to original sources

PubMed1995

Dependency on intercellular adhesion molecule recognition and local interleukin-2 provision in generation of an in vivo CD8+ T-cell immune response to murine myeloid leukemia.

The immune response to a murine myeloid leukemia (cell line C1498) was studied in vitro and in vivo. Natural killer (NK) cells and CD8+ cytotoxic T lymphocytes (CTL) were shown to lyse C1498 in vitro through the binding of leukocyte function antigen-1 (LFA-1) on effectors and intercellular adhesion molecule-1 (ICAM-1) and ICAM-2 on C1498 target cells. However, the ability of nonimmunized mice to resist an in vivo challenge of a low dose (10(4)) of C1498 was NK-cell, but not T-cell dependent. The failure of T cells to participate in the immune surveillance of a low leukemia burden appeared, in part, because of a lack of expansion of leukemia reactive CTL precursors (CTLp). Leukemia reactive CTLp frequency estimations in naive and leukemia bearing mice were not significantly different (range, 1:20,600 to 1:74,000) in contrast to immunized mice (range, 1:1,400 to 1:4,400). Leukemia reactive CTLp could be expanded to a level that could apparently mediate in vivo immune surveillance of 10(5) leukemia cells by injection of irradiated leukemia cells intraperitoneally (IP) or subcutaneously (SC), but not intravenously (IV). However, IV injection of 10(5) live leukemia cells engineered to secrete interleukin-2 (IL-2) resulted in systemic immunity mediated primarily by CD8+ T cells. We conclude that NK cells can mediate immune surveillance of a low leukemia burden. CD8+ CTL-mediated immune surveillance can eliminate a higher leukemia burden than NK cells, but requires T-cell help, which can be delivered by local IL-2. Both NK and CTL-mediated immune surveillance of C1498 murine myeloid leukemia is dependent on recognition through the LFA-1:ICAM adhesion pathway.

Animals↗

PubMed1995

B7-1 expression decreases tumorigenicity and induces partial systemic immunity to murine neuroblastoma deficient in major histocompatibility complex and costimulatory molecules.

Neuroblastoma may escape an immune attack by virtue of its low expression of surface accessory molecules essential in the antitumor response. Murine neuroblastoma, neuro-2a, was transduced with the retroviral vector LB7-1SN to examine the influence of B7-1 expression on the immune response directed against a low major histocompatibility class (MHC) I and class II negative, B7-2, and ICAM-1 negative tumor. Using a retroperitoneal model for implantation of neuroblastoma in its natural site, we demonstrated that expression of B7-1 by neuro-2a reduces its tumorigenicity. Coinjection of B7-1-positive and -negative cells improved survival compared with mice receiving B7-1-negative cells alone. This was dependent on the ratio of B7-1+ to B7-1- neuro-2a cells injected. CD8+ and not CD4+ T-cell depletion significantly increased tumor-induced mortality in syngeneic A/J mice, indicating that B7-1 decreases tumorigenicity primarily by direct constimulation of CD8+ T cells. Rejection of N-2a/B7-1 tumors or preimmunization with irradiated N-2a/B7-1 cells die not increase protection to challenge with unmodified neuro-2a cells over mice vaccinated with N-2a/neo. Furthermore, cytotoxic T lymphocyte (CTL) precursor frequencies were not significantly higher after in vivo priming and in vitro stimulation with irradiated N-2a/B7-1 compared with N-2a/neo, indicating that B7-1 costimulation by the tumor, in the absence of adequate antigen presentation by MHC molecules, may limit the generation of effective CTLs.

Animals↗

PubMed1994

Interleukin-2 gene transfer into murine neuroblastoma decreases tumorigenicity and enhances systemic immunity causing regression of preestablished retroperitoneal tumors.

Murine neuroblastoma, neuro-2a, was transduced with the retroviral vector LIL-2SN in order to examine the influence of localized interleukin (IL)-2 production on the immune response against a low major histocompatibility complex (MHC) class I, class II-negative, and intercellular adhesion molecule (ICAM)-1-negative tumor. Two neomycin-resistant (neo R) clones, N-2a/IL-2/L (2.5 +/- 0.4 U/ml/10(6) cells/24 h) and N-2a/IL-2/H (44.6 +/- 8.8 U/ml), were studied as representative low and high IL-2 producers, respectively. Using a recently developed retroperitoneal (r.p.) model for implantation of neuroblastoma in its natural site, we demonstrated that production of IL-2 by neuro-2a reduces its tumorigenicity in a dose-dependent fashion. T-cell, but not natural killer (NK) cell, depletion significantly increased tumor induced mortality in syngeneic A/J mice. Mice genetically devoid of T-cells (C.B-17 scid/scid) also experienced a significant increase in mortality rates. This indicates that the antitumor effect of locally secreted IL-2 is mediated primarily through activation of T-cells. Immunization of mice with irradiated N-2a/IL-2/H cells resulted in protection when challenged at a later date with unmodified neuro-2a cells. Depletion of CD8+, but not CD4+, T-cells prior to vaccination abrogated the protective effect, indicating that the priming phase of the immune response is CD8+ T-cell dependent. Mice with established r.p. tumors were vaccinated with N-2a/IL-2/H, which significantly prolonged their survival compared to unimmunized controls and to mice immunized with non-IL-2-producing neuro-2a cells. Because of the similarities of this model with the human tumor, our studies indicate that IL-2-transduced neuroblastoma cells may be effective in generating systemic immunity leading to eradication of minimal residual disease.

Animals↗