Establishment of Cell-to-Cell Contact by Adoptively Transferred Adherent Lymphokine-Activated Killer Cells With Metastatic Murine Melanoma Cells

Abstract

A murine model of pulmonary B16 melanoma was used to study the infiltration into metastases of lymphokine-activated killer (LAK) cells and adherent lymphokine-activated killer (A-LAK) cells and, specifically, to study whether A-LAK cells are able to leave the tumor microcirculation and establish cell-to-cell contact with malignant cells. Fluorescence microscopy demonstrated that A-LAK cells accumulated in metastases twice as efficiently as LAK cells during interleukin-2 stimulation. Electron microscopy of pulmonary metastases 16 hours after administration of 2.5 x 10(7) A-LAK cells revealed A-LAK cells, identified by the presence of typical two-compartment granules, in direct contact with melanoma cells. This finding was confirmed by using A-LAK cells prelabeled with polycationized ferritin. In conclusion, our observations demonstrate unambiguously the ability of adoptively transferred A-LAK cells to establish contact with extravascular metastatic melanoma cells.

High Dose IL‐2‐Activated Murine Natural Killer (A‐NK) Cells Accumulate Glycogen and Granules, Lose Cytotoxicity, and Alter Target Cell Interaction In Vitro

“…Later on, the vesicular region developed complex lamellated formations, irregular amorphous structures, and also contained probable glycogen particles. The latter findings might implicate that these lysosomal structures [13] are involved in intracellular scavenging of cytoplasmic constituents besides uptake of extraneous material [13,18]. Since two-compartment granules are generally also considered to be exocytosed towards target cells during cytotoxic events [15][16][17], and it was observed by us that A-NK cell cytotoxicity decreased with time, the described advanced morphology of granules might be related to degenerative alterations, including loss of cytolysis-mediating function.…”

“…Apparently, this second developmental phase of A-NK cells in culture has attracted little attention before. The question obviously arises whether this was a pure in vitro phenomenon or if young A-NK cells, tested to be cytolytically active, undergo similar changes after adoptive transfer to a tumour-bearing animal during the continued lymphokine administration to the recipient and after tumour infiltration [18,26,27]. Such a development would contribute to the understanding of therapy failure after AIT with LAK cells.…”

“…In an environment of extracellular matrix components the A-NK cells likewise developed such cytoplasmic accumulations over a 24 h interval while interacting with target cells and showed signs of phagocytic activity [25]. The mentioned structural variations were very obviously associated with an increase in cellular size, which is a variable of paramount importance considering that AIT (intravenous or loco-regional) is performed under the assumption that the LAK cells will eventually establish contact with the malignant growth, as has been demonstrated in several experimental systems [18,26,27]. Inevitably, the relocation of effector cells that leads to their intratumoural accumulation will depend on the rheological properties of the cells while in the microcirculation or in the interstitium, i.e.…”

“…The very characteristic two-compartment (specific or lytic) cytoplasmic granules that define LGLs [12] contain perforin and serine esterases (granzymes) [13,14] and are assumed to be involved in cytolytic action by exocytosis of their content [15][16][17]. However, whereas cells intended for adoptive transfer to tumour-bearing animals after having been propagated for 4-5 days in the presence of IL-2 are granular [18], the granules are not present in discernible amounts in their progenitors of isolated spleen cells. Furthermore, we have demonstrated that the A-NK cells accumulate increasing amounts of multi-catalytic protease complex (proteasome) into enlarging cytoplasmic pools of an electron lucent material [19].…”

Trafficking of activated lymphocytes into the RENCA tumour microcirculation in vivo in mice

“…However, this was a xenogenic model using human LAK cells in a rabbit tumour implanted into the rabbit ear, thus, the significance of these observations may be limited. A subsequent paper by the same authors used a syngeneic model to investigate the migration and localization of murine activated natural killer (NK) cells into a murine mammary carcinoma grown in a cranial window preparation (Sasaki et al, 1991) and syngeneic models (Basse et al, 1991;Fukumura et al, 1995;Melder et al, 1995).…”