Naturally cytotoxic tonsillar lymphocytes: a manifestation of heterogeneity among human NK cells

Phenotyping of mononuclear cells from tonsils and corresponding biopsies using a cytofluorimeter. A comparative study

A series of B, T, natural killer cell (NK) and monocyte-specific monoclonal antibodies was used to determine the distribution of lymphocyte subpopulations in cell suspensions obtained from whole tonsils as well as their corresponding biopsies. The majority of the mononuclear cells stained with OKB-7 and anti-Dr. A consistent lower percentage of the B lymphocytes stained with OKB-2. The T lymphocytes were composed of a majority of OKT4+ lymphocytes. Only a minority of the lymphocytes stained with Leu-7, whereas Leu-llb+ lymphocytes were virtually absent. A significant proportion of the mononuclear cells stained with OKM-1. There was a highly significant correlation between the distribution of the cells stained with the different monoclonal antibodies obtained from the whole tonsil and the corresponding biopsy (r2 = 0.95). This study shows that biopsies offer a reliable source to study the lymphocyte subsets in tonsils and that cytofluorimetry can be applied to study the lymphocyte distribution in this organ.

Naturally cytotoxic tonsillar leukocytes: phenotypic characterization of the effector population

Human palatine tonsil sections were examined to investigate the distribution of cells bearing the cell surface markers of peripheral blood natural killer (PB-NK) cells. Leu-7+ (HNK-1+) cells were localized predominantly in lymphoid follicles, whereas OKM1-, Mac-1-, and Mo2-labelled cells were found in the epithelial and subepithelial regions and epithelial crypts. OKT10+ cells showed a variable distribution, being found in follicles and interfollicular or subepithelial regions. No. B73.1+ cells could be identified in tonsil sections. Leu-7+ cells appeared not to be responsible for tonsillar natural cytotoxicity, since Leu-7 (HNK-1) antibody- and complement-mediated lysis under conditions that markedly reduced PB-NK activity failed to abolish cytotoxicity, and positive selection by means of the FACS IV gave no enrichment of activity. Similarly, cells labelled with the antibodies B73.1, Leu-11b, OKT8, OKT10, and TDR 31.1 (anti-major histocompatibility complex class II framework determinant) were not enriched with regard to NK activity either. However, positive selection with OKM1, Mac-1, or Mo2 showed that cells bearing these markers were responsible for essentially all tonsillar NK activity. No large granular lymphocytes were identified in such populations enriched for NK activity. The observation that PB-NK cells labelled faintly with Mo2 weakens the argument that a non-adherent mononuclear phagocyte population was responsible for the activity. These data therefore support the existence of heterogeneity within naturally cytotoxic cell populations.

Native and inducible levels of natural cytotoxicity in lymph nodes draining mammary carcinoma

Lymphocytes isolated from axillary nodes draining breast carcinoma possess variable natural cytotoxic capacity. Augmentation of lymph node cell (LNC) cytotoxicity by interferon (IFN) is also variable, with only some populations displaying potentiated lysis following exposure to either IFN-a or gene-cloned IFN-a2. Where present the IFN-induced augmentation of LNC cytotoxicity was invariably weaker than that observed following similar treatment of autochthonous peripheral blood mononuclear cells (PBMC). Irrespective of their responsiveness to IFN the cytotoxic activity of all LNC preparations examined was significantly increased following pre-incubation with either staphylococcal enterotoxin A (SEA) or factors elaborated by lectin-pulsed allogeneic LNC. THe induction or amplification fo LNC-mediated natural cytotoxicity by lymphokines may provide a local potentiation of natural immune function at the host : tumour interface.