In vitro and in vivo effects of cisplatin on the generation of lymphokine-activated killer cells.

Pretreatment of human peripheral blood lymphocytes (PBL) with cisplatin (CDDP) before in vitro culture with interleukin-2 (IL-2) inhibited the generation of lymphokine-activated killer (LAK) cells and strongly inhibited proliferation. This inhibition was dose dependent, was significant only at concentrations greater than 6 microM, and it required exposure to the drug for more than 1 hour. This period of IL-2 unresponsiveness was maximum at 6 hours, but was spontaneously recovered within 24-48 hours and was more rapidly restored by increasing dosages of IL-2. Because inhibition of the generation of LAK cells by CDDP was observed only at relatively high levels of exposure to the drug (greater than 6 microM for greater than 1 hr), it was important that we explore the in vivo significance of these findings. The peripheral blood lymphocytes from patients bearing ovarian adenocarcinoma collected 1 hour after an iv infusion of 50 mg of CDDP/m2 were not inhibited, compared with those collected immediately before therapy. Relatively high levels of exposure to CDDP are required for inhibition of the generation of new cytotoxic effectors, most likely because of its antiproliferative effect. These results may bear relevance to approaches involving the combined use of CDDP and IL-2-LAK.

Killing of tumor cells with pleiotropic drug resistance by OK432-activated effector cells.

The inactivate streptococcal preparation OK432 activates the cytotoxic function of natural killer (NK) cells. Moreover, it induces cytotoxic activity against freshly isolated tumor cells. The present study was aimed at assessing whether OK432-activated effector cells expressed cytotoxicity against tumor cells pleiotropically resistant to cancer chemotherapy agents. OK432-treated lymphoid cells killed the multidrug resistant (MDR) LOVO DX line as efficiently as drug sensitive parental LOVO N carcinoma line. Effector cells involved in killing MDR cells were low density large granular lymphocytes with NK functions. Activation of effector cells has the potential to complement conventional cytoreductive therapy by eliminating residual-tumor cells surviving and resistant to chemotherapy.

Treatment with modified heparins inhibits experimental metastasis formation and leads, in some animals, to long-term survival.

Two chemically modified heparins with low anticoagulant activity were studied in terms of their antimetastatic activity in the B16-BL6 melanoma model. The two heparins were a very low molecular weight heparin (VLMW-H) and a low molecular weight heparin with 100% succinylation of desulfated N groups (Succ100-LMW-H). Both heparins, VLMW-H more so than Succ100-LMW-H, were highly effective in decreasing the number of lung metastasis on day 21 when administered once subcutaneously 10 min before intravenous injection of melanoma cells or 2 times/week for 3 weeks. When the time of survival was measured, both heparins did not significantly prolong survival when administered once before injection of the tumor cells. When a repeated treatment schedule was adopted over 3 weeks, both heparins led to a slight, yet significant prolongation of survival. When the repeated treatment protocol was continued beyond 3 weeks, a highly significant prolongation of survival was observed with VLMW-H and there were some long-term survivors (20% for VLMW-H and 10% for Succ-LMW-H) that remained disease-free after discontinuation of therapy on day 90. The present results confirm and reinforce the concept that heparins with reduced anticoagulant activity may have interesting therapeutic applications in the prevention of tumor metastasis.

T-cell receptor gene rearrangements and expression in normal human large granular lymphocytes (LGL) and their pathological expansions.

The lineage to which normal large granular lymphocytes/natural killer (LGL/NK) cells belong is controversial; in fact they share some surface markers and functional activities with monocytes, but also with T lymphocytes. The relationship of LGL to the T cell lineage by analysis with the T cell receptor (T-rec) gene has been investigated. Pure preparations of human LGL and their CD11(+) CD8(-) and CD11(-) CD8(+) subsets had the Tß gene in its unrearranged germline configuration. Expression of Tα and Tß genes was not detectable. The organization of Tγ gene, which is of particular importance because it occurs early in T cell ontogeny, was also found in its germline configuration.A rare type of lymphoproliferative disorder, termed Tγ-LPD, is characterized by expansion of cells very similar to LGL for morphology, phenotype, and functional activity. Of 17 patients with Tγ-LPD studied for T-rec rearrangement, 15 displayed rearrangement of Tß and Tγ loci and were CD3+ (14/15 had monoclonal rearrangement), while 2 cases were in germline configuration and were CD3-. Similarly to very small subsets of CD3+ LGL recently described, most Tγ-LPD cases are CD3+ and have T-rec genes rearranged. These data suggest that either a subset of LGL or a particular step of differentiation may be related to the T cell lineage; they also demonstrate that, in contrast to previous views, most TγLPD are monoclonal, presumably neoplastic, lymphoproliferative disorders.

Lymphocytes infiltrating ovarian carcinoma: modulation of functional activity by intraperitoneal treatment with biological response modifiers.

A better understanding of the immunobiology of tumor-associated lymphocytes (TAL) may have considerable bearing on the therapeutic perspective of human neoplasia. We have identified ovarian cancer as a clinical condition privileged for studies on immunity and its in vitro and in vivo modulation. Our previous studies on the mechanisms of natural resistance have shown that TAL from ovarian carcinoma have defective natural killer cell activity when compared to peripheral blood lymphocytes from the same patient. This low natural killer cell activity could be stimulated in vitro by biological response modifiers (e.g. interferons) and these findings led us and others to design clinical trials based on intraperitoneal infusions of these agents. Interleukin-2 was extremely effective at inducing or augmenting cytotoxicity in TAL (lymphokine-activated killer cell activity). TAL-generated lymphokine-activated killer cells were cytotoxic against autologous and allogeneic fresh carcinoma cells. This finding provides a rationale for direct intraperitoneal infusion of this cytokine in ovarian cancer.

Perinatal transmission of the hepatitis B virus and of the HBV-associated delta agent from mothers to offspring in northern Italy.

We report a prospective study on infants born to hepatitis B surface antigen (HBsAg) carrier mothers to estimate the incidence of perinatal transmission of HBV and HBV-associated delta agent in Northern Italy. The risk of infection to the infant was related to the presence of the HBe antigen-antibody system, HBV-specific DNA polymerase activity and antibody to delta in maternal sera, and to the titer of anti-HBe in babies at birth. The data of this study indicate: 1. Babies born to HBsAg carrier mothers with HBeAg in serum are at extremely high risk of acquiring HBV infection and of developing a chronic carrier state, whereas those born to anti-HBe-positive mothers are at a lower (P less than .01) yet consistent risk of infection. 2. HBs antigenemia is usually prolonged and symptomatic in babies born to HBeAg-positive mothers while being self-limited and asymptomatic in babies born to anti-HBe-positive mothers. 3. DNA polymerase activity in maternal serum appears to be the most sensitive marker predicting HBV transmission to the infant since it was detected in all the HBeAg-positive mothers and also in two anti-HBe-positive mothers and in one HBeAg/anti-HBe-negative mother who transmitted infection to their babies. 4. High titers of anti-HBe (up to 1:103) do not prevent HBV infection. 5. Vertical transmission of delta infection seems to occur only in circumstances that permit perinatal transmission of HBV infection.