K cell activity is low in newborn infants

K cell activity of 18 mature, healthy newborns was measured against O,Rh(D)-positive erythrocytes, sensitized by anti-D antibodies, in cord and venous blood (later obtained 3-4 days after delivery). 53 healthy women served as controls. Activity was determined as a function of target cell number in the enzyme-like kinetic model of cytotoxicity. It was low in cord blood, increased in venous blood by days 3-4 but it did not reach the level of adults. While cytotoxic activity of male infants increased significantly from birth to the 3rd-4th day of life, it did not change in female infants. No correlation was found between the weight and K cell activity of newborns.     

The suppressive effect of progesterone on lymphocyte cytotoxicity: unique progesterone sensitivity of pregnancy lymphocytes

The effect of progesterone on the cytotoxic activity of lymphocytes obtained from healthy pregnant women, women with threatened pre-term delivery, healthy non-pregnant women and healthy male donors has been compared. The cytotoxic activity of lymphocytes from healthy pregnant women was significantly reduced by progesterone at concentrations present in the serum during pregnancy. In contrast, a 100-fold higher concentration of progesterone was required to diminish the cytotoxic activity of lymphocytes from women with threatened pre-term delivery and from healthy male donors. Individuals with lymphocytes of high and low progesterone sensitivity could be found amongst non-pregnant women. The results of investigations at the single cell level suggested that although progesterone did not inhibit the ability of the lymphocytes to bind to the target cells, it markedly reduced the target cell lysing capacity of the bound effector cells.     

Deficient antiendometrium lymphocyte-mediated cytotoxicity in patients with endometriosis

OBJECTIVE: To study the possible role of the immune system in the pathogenesis of endometriosis. DESIGN: A cytotoxicity assay by 51Cr release was performed to determine the lymphocyte cytotoxic response toward endometrial targets and an erytroleukemic cell line (K562). SETTING: The assays were performed in an academic research environment. PATIENTS, PARTICIPANTS: Twenty-five control women and 25 patients with endometriosis were selected on the basis of laparoscopic examination. INTERVENTIONS: The lymphocyte cytotoxic activity was evaluated separately on endometrial stromal and epithelial cells after 4 hours' incubation. MAIN OUTCOME MEASURE: The study was designed to determine, in controls and endometriosis patients, the lymphocyte-mediated cytotoxicity toward stromal and epithelial cells of endometrium. RESULTS: The lymphocyte response in the presence of stromal cell antigens was significantly lower (P less than 0.02) in disease-affected women when compared with that obtained in controls (2.89 +/- 0.87 and 7.64 +/- 1.66, respectively). In contrast, when the same assay was performed on K562 cells, no difference was observed between endometriosis patients and controls. CONCLUSIONS: These data suggest that an altered immune recognition might be one of the pathogenic mechanisms of endometriosis. Moreover, they indicate that this is not a general phenomenon but is specific for the endometrial target.     

The subpopulations of T lymphocyte and the function of suppressor T cell in normal pregnancy and pregnancy-induced hypertension

T-lymphocyte subpopulations were determined by the monoclonal antibodies (OKT3, OKT4, OKT8) in 20 cases of normal pregnancy, 36 cases of pregnancy-induced hypertension (PIH) and 20 cases of normal non-pregnant women. The assaying of ConA-induced suppressor T cell (Ts cell) function was carried out in another 20 cases of late pregnancy, 20 cases of moderate and severe PIH, and 10 cases of normal non-pregnant women. The results showed: the percentage of Ts cell increased significantly and the ratios of Th/Ts decreased significantly during normal pregnancy as compared with normal non-pregnant women. As compared with the late pregnant women, a lowering of Ts cell and elevating ratio of Th/Ts were found in PIH cases with statistical significance in severe PIH. A decrease of Ts cell function was also seen in moderate and severe PIH cases. All these findings suggest that the changes of Ts cell in amount and function may play an important role in maintaining normal pregnancy and in the pathogenesis of PIH.     

Induction of ovarian tumor-specific CD8+ cytotoxic T lymphocytes by acid-eluted peptide-pulsed autologous dendritic cells

OBJECTIVE: To evaluate the potential of dendritic cells pulsed with acid-eluted peptides derived from autologous ovarian cancer cells for eliciting a tumor-specific cytotoxic T cell response in women with advanced ovarian cancer. METHODS: CD8+ T lymphocytes derived from peripheral blood mononuclear cells stimulated in vitro with autologous ovarian tumor peptide-pulsed dendritic cells were tested for their ability to induce an HLA class I-restricted cytotoxic T lymphocyte response against autologous tumor cells. To correlate cytotoxic activity by cytotoxic T lymphocytes with T cell phenotype, we used two-color flow cytometric analysis of surface markers and intracellular cytokine expression (interferon-gamma versus interleukin-4). RESULTS: CD8+ cytotoxic T lymphocyte responses against autologous ovarian tumor cells were elicited in three consecutive women who had advanced ovarian cancer. Although cytotoxic T lymphocyte populations from all women expressed strong cytolytic activity against autologous tumor cells, they did not lyse autologous lymphoblasts or Epstein-Barr virus-transformed cell lines, and they showed negligible cytotoxicity against the natural killer-sensitive cell line K-562. Cytotoxicity against the autologous tumor cells was significantly inhibited by anti-HLA class I (W6/32) and anti-HLA-A2 (BB7-2) monoclonal antibodies. CD8+ cytotoxic T lymphocytes expressed variable levels of CD56 and preferentially expressed interferon-gamma rather than interleukin-4. CONCLUSIONS: Peptide-pulsed dendritic cells induced specific CD8+ cytotoxic T lymphocytes that killed autologous tumor cells from women with advanced ovarian cancer. This finding might contribute to the development of active or adoptive immunotherapy for residual or resistant ovarian cancer after standard surgery and cytotoxic treatment.     

NK and trophoblast cells interaction: cytotoxic activity on recurrent pregnancy loss

Abstract

The trial objective was to determine the peripheral blood NK cells cytotoxic activity effect on trophoblast cells at recurrent pregnancy loss (RPL). The investigation involved non-pregnant women with PRL in proliferating and secretory menstrual cycle phases (PMCPh and SMCPh, respectively); women of 6–7 weeks pregnancy with RPL in past medical history; healthy fertile non-pregnant women in PMCPh and SMCPh, women of 6–7 weeks physiological pregnancy, nulliparity healthy women with regular menstrual function in PMCPh and SMCPh. NK cells cytotoxic activity was determined using peripheral blood mononuclear cells. The target cells were JEG-3?line trophoblasts. It has been established that NK cells cytotoxic activity effect on trophoblasts is lower in SMCPh than in PMCPh in non-pregnant fertile women. The NK cells cytotoxic activity was higher in SMCPh than in PMCPh in non-pregnant women with PRL and also higher than the same value in SMCPh in non-pregnant fertile women. The increased NK cells cytotoxic activity values in SMCPh in women with RPL may be the reason for miscarriage.     

Protocol combining GnRH agonists and GnRH antagonists for rapid suppression and prevention of gonadal damage during cytotoxic therapy

PURPOSE OF INVESTIGATION: Infertility represents one of the main sequelae of cytotoxic therapy given for various malignant diseases. Because dividing cells are more sensitive to cytotoxic effects than are cells at rest, it has been hypothesized that inhibition of the pituitary-gonadal axis may facilitate the preservation of future gonadal function. The aim of our study was to find a quick, reliable and economic way to suppress the pituitary-gonadal axis by combining GnRH-agonists with GnRH-antagonists in order to preserve future gonadal function. METHODS: A combination of D-Trp6-GnRH-a (3.75 mg) and cetrorelix (3 mg) was used to achieve a quick downregulation in six postmenarchal young women (aged 15.4 +/- 0.7) years with haematological malignancies before the onset of cytotoxic chemotherapy. RESULTS: The combination of D-Trp6-GnRH-a and GnRH-antagonist cetrorelix induced a reliable and long-lasting suppression of gonadotrophin secretion within 96 hours in all patients allowing cytotoxic therapy to be started without any delay. CONCLUSIONS: The combination of GnRH-agonist and GnRH-antagonist enables a rapid, reliable and cost-effective suppression of the pituitary-gonadal axis to be achieved. Future gonadal function of treated patients will be monitored.     

Influence of menstrual cycle on NK activity

Natural killer (NK) cells are CD3⁻ CD56⁺ and/or CD16⁺ cytotoxic lymphocytes that mediate first-line defense against various types of target cells without prior immunization. To assess the effect of the menstrual cycle and gender on NK activity we evaluated 30 healthy women (mean age 28.1 years, range 21–39) in follicular and luteal phases, 29 postmenopausal women (mean age 58.8 years, range 42–72) and 48 healthy men (mean age 31.6 years, range 21–40). In a flow cytometric test of NK activity, peripheral blood mononuclear effector cells were mixed with K562 targets cells labeled with DiO (3,3′-dioctadecyloxacarbocyanine perchlorate) at effector:target cell ratios of 40, 20, 10 and 5:1. Dead cells were stained with propidium iodide and results were expressed as lytic units per 10⁷ cells. In addition, progesterone levels were determined in the luteal phase of the menstrual cycle of healthy women by a chemiluminescence assay. Our results showed that (1) NK cytotoxicity was higher in the follicular than in the luteal phase of the menstrual cycle (P<0.0001); (2) postmenopausal women and men showed NK activity similar to women in the folicular phase but higher than women in the luteal phase of the menstrual cycle (P<0.05); and (3) there was no correlation between NK activity and levels of progesterone. The data suggest that progesterone does not influence NK activity directly and that other factors may explain the reduction of NK activity in the luteal phase of the menstrual cycle.     

Evidence of endothelial cytotoxic compounds in placental extracts from preeclamptic women

OBJECTIVE: To determine whether placenta and plasma of preeclamptic women contain factors that cause endothelial cell damage. METHODS: Placental extracts and plasma from preeclamptic and normotensive women were added to cultures of normal human umbilical vein endothelial cells and their effect on their viability, was determined by MTT reduction and 51chromium release. RESULTS: Placental extracts from normotensive and preeclamptic women were cytotoxic to endothelial cells, but not the plasma from both groups. Mean +/- standard deviation values of cytotoxicity index in preeclamptic and normotensive placental extracts using the MTT reduction were 70.3 +/- 6.76% and 51.4 +/- 8.81%, respectively, showing a significant difference (P < .0001). Using the 51chromium-release assay, preeclamptic placental extracts showed cytotoxic effects of 87.6 +/- 13.47% compared with 17 +/- 20.60% in control patients. The cytotoxic activity decreased after trypsin digestion and heat treatment in both groups. CONCLUSIONS: A cytotoxic factor to endothelial cells in placental extracts of preeclamptic women was identified. This compound is thermolabile and sensitive to trypsin digestion.     

Peripheral large granular lymphocytes in normal pregnant and postpartum women: decrease in late pregnancy and dynamic change in the puerperium

Large granular lymphocytes (LGLs) have a variety of cytotoxic activities of NK, K and cytotoxic T lymphocytes, suggesting that their morphology is indicative of lytic function. In non-pregnant normal control women (n = 48), the number of LGLs was 0.30 +/- 0.14 x 10(9)/l and the proportion of LGLs in their peripheral lymphocyte fraction was 14.0 +/- 5.4%. The number and proportion of LGLs were significantly decreased in the third trimester of pregnancy (n = 32; 0.19 +/- 0.08 x 10(9)/l, P less than 0.01, and 11.7 +/- 3.8%, P less than 0.05), although an unexpected increase in the proportion of LGLs was observed in the first trimester of pregnancy (n = 24; 17.5 +/- 6.5%, P less than 0.05). After delivery, the number and proportion of LGLs increased rapidly to restore the non-pregnant levels and showed a marked increase in LGL count 4 months postpartum. These data suggest that lymphocyte-mediated cytotoxicity decreases in late pregnancy and increase dynamically after delivery to restore the non-pregnant state.     

Low susceptibility of choriocarcinoma cell lines to lymphokine activated killer (LAK) cells

We investigated the anti-tumor effect of lymphokine activated killer (LAK) cells on various carcinoma cell lines as it may play an important role in the immunotherapy of gynecologic cancers. Peripheral blood lymphocytes (PBL) were cultured in 10 U/ml of recombinant interleukin-2 (rIL-2). The cytotoxic action of LAK and natural killer (NK) on carcinoma cell lines was measured by a standard 4-hr 51Cr-releasing assay. Daudi and RPMI 1788, NK resistant B cell lines were lysed by rIL-2 activated PBL although they were not killed by human fresh PBL. LAK cells thus induced were markedly cytotoxic to sixteen carcinoma cell lines. However, five choriocarcinoma cell lines were resistant to LAK action because specific action was less than 30% at effector/target ratio of 20. The cold target competitive inhibition experiments showed that the choriocarcinoma cell line GCH-1 induced much lower inhibition than Daudi cells. These results indicate that the low susceptibility of the choriocarcinoma cell lines to LAK cells could be due to the lack of the effector molecules recognized by killer cells.     

Preeclampsia is associated with a serum factor cytotoxic to human endothelial cells

Preeclampsia occurs in 7% to 10% of pregnancies and is a leading cause of morbidity for mothers and their infants. Intensive investigation has failed to reveal the cause of the multiple organ dysfunction characteristic of this disorder, which abates completely with delivery. However, several observations suggest that endothelial cell dysfunction is a central pathophysiologic event. We report that serum from preeclamptic women is cytotoxic to endothelial cells in vitro. Consistent with the reversal of the clinical condition after delivery, cytotoxic activity in serum of preeclamptic women is reduced after 24 to 48 hours post partum. In contrast, cytotoxic activity of serum from normal pregnant women increases after delivery.     

Histocompatibility leukocyte antigen-G is not expressed by endometriosis or endometrial tissue

OBJECTIVE: The immunological mechanisms that support persistence and proliferation of ectopic endometrial implants within the peritoneal cavity of women with endometriosis are unknown. Inhibition of natural killer (NK) and cytotoxic T-cell function has been proposed as a mechanism. We tested the hypothesis that expression of a nonclassical major histocompatibility antigen, HLA-G, might explain the local immunosuppression associated with ectopic endometrium. DESIGN: Nested case-control study of women with and without laparoscopic evidence of endometriosis. SETTING: Reproductive endocrinology clinic at a university hospital. PATIENT(S): Peritoneal fluid specimens from 10 women with revised AFS stage I-IV endometriosis and from 10 age-matched normal controls without laparoscopic evidence of endometriosis were tested for the presence of HLA-G protein. Endometriosis and normal endometrial biopsies from four patients were used to prepare stromal cell cultures directly evaluated for HLA-G protein. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): The expression of HLA-G in peritoneal fluid, tissue, and cell cultures was determined by immunoblotting with a specific monoclonal antibody. RESULT(S): HLA-G protein was not detectable in peritoneal fluid specimens of endometriosis patients or controls. Moreover, ectopic and normal endometrial tissues and stromal cells did not express HLA-G. CONCLUSION(S): Immune cell inhibition in endometriosis must be mediated by factors other than HLA-G.     

Gains and losses of CD8, CD20 and CD56 expression in tumor stroma-infiltrating lymphocytes compared with tumor-associated lymphocytes from ascitic fluid and lymphocytes from tumor draining lymph nodes in serous papillary ovarian carcinoma patients

Serous papillary ovarian cancer (SPC) is a highly aggressive tumor. About two-thirds of women have advanced disease at the time of diagnosis. Although many women with disseminated disease respond at first to combinations of surgery and chemotherapy, nearly 90% of tumors recur and women die of disease. Update progress in our knowledge of tumor-associated antigens and insight into mechanisms involved in immune-mediated recognition of these antigens, have provided a strong starting point for using the immune system as a model for novel therapy. In this study we determined the immunological profile of tumor-infiltrating lymphocytes (TILs), tumor-associated lymphocytes (TALs) in ascitic fluids, and lymphocytes from tumor draining regional lymph nodes (LNs) in SPC patients by CD20 (L26), CD8, and CD56 immunostaining. We examined 14 cases of TILs, 15 cases of TALs and 19 cases of LNs. TILs were infiltrating tumor stroma. No significant difference was detected in TILs, TALs and LNs in the expression of the B-cell marker CD20. In contrast, CD8 (T-cytotoxic) and CD56 (natural killer cell, NK) markers were dominant in LNs and TALs, but not in TILs. We conclude that SPC tumor lymphocytic infiltrate demonstrates a deplete T cytotoxic (CD8+) and NK cell (CD56+) immunophenotypic profile. This might in part explain the poor clinical outcome of the disease.     

Peripheral blood natural killer cell proportion and ovarian function in women with recurrent implantation failure

Abstract

Current knowledge of the association between peripheral natural killer (NK) cell proportion and ovarian function in reproductive-age women is limited. We explored the association between NK cell proportion and ovarian function in women who underwent in-vitro fertilization (IVF) treatment. This was a retrospective cohort study using the data of 20–44-year-old women with recurrent implantation failure (RIF) who were tested for NK cell proportion and anti-Müllerian hormone (AMH). Indicators of ovarian function included AMH, observed-to-(age-appropriate) reference AMH ratio, high FSH, peak E₂ and total number of oocytes during the first IVF cycle following the test. We used different model specification controlling for women’s age, and body mass index. Among a total of 936 women, majority showed lower AMH compared to age-appropriate level. Average NK cell proportion was 13.5?±?5.7%. Number of oocytes showed positive association with NK cell (ß?=?0.040, p?=?.025). In the subgroup with NK ≥ 18%, NK cell proportion was negatively associated with AMH (?0.106, p?=?.012), AMH ratio (?0.049, p?=?.014) and number of oocytes (?0.021, p?<?.001) while the associations with others remain close to null. High NK cell proportion may be harmful to ovarian reserve or function.     

Granulosa cell tumor of the ovary: a population-based study of 37 women with stage I disease

OBJECTIVES: The goal of this work was to evaluate clinical and pathological findings, surgical procedures, and postoperative treatment in women with stage I granulosa cell tumor. METHODS: Data for 49 women with granulosa cell tumor were collected retrospectively. All pathological sections and findings were reviewed from diagnosis until recently. Follow-up data were collected from the general practitioner, hospital records, or death certificate. Fisher's exact test, Student's t test, Mann-Whitney test, and Kaplan-Meier survival analysis were applied, as appropriate. RESULTS: Thirty-seven women of median age 58 years (range, 33-82) were diagnosed in stage I. Follow-up time was 8 years (range, 8 months to 26 years). The estimated survival for stage I was 93% at 5 years, 84% at 10 years, and 62% at 20 years; the actual survival rates were 94, 82, and 62% after 5, 10, and 20 years, respectively. Primary treatment consisting of total abdominal hysterectomy and bilateral salpingo-oophorectomy was associated with improved survival (P < 0.05) and tended to be associated with longer relapse-free interval (P < 0.06). The 10-year survival rate was 40% in postmenopausal women operated conservatively and more than 90% for the extensively treated women (P < 0.05). Evidence of increased estrogen secretion was found more often in postmenopausal woman as compared with premenopausal women (P < 0.01) but did not affect survival. No pathological parameter correlated with prognosis. CONCLUSION: Granulosa cell tumor is a tumor of unquestionable malignant potential and has a tendency for late relapses. Long-time follow-up is recommended.     

Prevention of vitamin K deficiency in the early neonatal period--prophylactic oral administration of VK to the mother

We studied the effect of vitamin K(MK-4) on the prevention of vitamin K deficiency in the early neonatal period. MK-4 (20 mg/day) was given orally for 1-7 days to 183 pregnant women at 37-39 weeks gestation. In the MK-4 treated group, there were no cases of melena neonatorum but there were 9 cases in the untreated group (9/757, 1.2%). To investigate the influence of MK-4 administration on liver function and the VK dependent coagulation system, maternal and umbilical venous blood were taken to measure T-Bil, GOT, GPT, gamma-GTP, LDH, and II, VII, X activity and HPT. There was no significant difference between these values in MK-treated and untreated groups. MK-4 concentrations were measured in the maternal and umbilical venous blood of 68 subjects. The level of MK-4 in umbilical venous blood was less than 0.1 ng/ml in 17 of 21 subjects not treated with MK-4 but it was over 0.1 ng/ml in 30 of 47 MK-4 treated subjects. However, no MK-4 was detected in 6 of 8 subjects who were treated for 1 day. The level of MK-4 in maternal blood was less than 0.1 ng/ml in 12 of 21 untreated subjects but it was 0.19-92.6 ng/ml in all of the 47 MK-4 treated subjects. The mean MK-4 concentration in cord blood as a percentage of that in maternal blood was 17.9%. These findings indicate that MK-4 is effectively transported from maternal to fetal blood through the placenta and its administration to pregnant women is useful in preventing melena neonatorum.     

Galectin-3 may contribute to Cisplatin resistance in clear cell carcinoma of the ovary

Our previous findings suggested that lower cell proliferation of clear cell carcinoma (CCC) of the ovary may contribute to its resistance to chemotherapy. We conducted the present study to find the gene that regulates cell proliferation of CCC and to elucidate whether it contributes to cisplatin (CDDP) resistance. Complementary DNA microarray analysis revealed that the gene expression level of galectin-3 of CCC cell lines (KK, RMG-I, HAC-2) was over threefold higher than that of ovarian serous adenocarcinoma (SAC) cell lines (HRA, KF). S-phase fraction increased after knocking down galectin-3 using small interfering RNA in RMG-I, KK, and HAC-2 cells. The protein expression of p27 decreased after knocking down galectin-3. CDDP-induced apoptosis was increased after knocking down galectin-3, and this cytotoxic effect was canceled by roscovitine. Immunohistochemical staining showed that galectin-3 expression in tumors of 20 CCC was significantly more frequent than that of 20 SAC (70.0% vs 15.0%, P = 0.0004). The present study showed that the expression of galectin-3 in CCC might contribute to its lower cell proliferation and lead to CDDP resistance.     

Cytokine production in natural killer cells and lymphocytes in pregnant women compared with women in the follicular phase of the ovarian cycle

OBJECTIVE: To test whether peripheral natural killer (NK) cells, helper T cells, and cytotoxic lymphocytes of pregnant women shift from a type 1 cytokine production toward a type 2 cytokine production as compared with these cells in women in the follicular phase. DESIGN: Prospective study. SETTING: Outpatient clinic. PATIENT(S): Healthy nullipara at 30 weeks' amenorrhea and healthy nonpregnant women in their follicular phase. INTERVENTION(S): Samples of whole blood were stimulated with phorbol myristate acetate (PMA; Sigma Chemical Co., St. Louis, MO) and Ca-ionophore in the presence of monensin (Sigma). Lymphocytes were stained with alpha-CD3, alpha-CD8, and alpha-interferon gamma (IFN-gamma) alpha-interleukin 2 (IL-2), IL-4, or IL-10. Analysis was performed by flow cytometry. Statistical evaluation was done with the Mann-Whitney U test. MAIN OUTCOME MEASURE(S): Percentage NK cells, helper lymphocytes, and cytotoxic lymphocytes that were producing IFN-gamma, IL-2, IL-4, or IL-10. RESULT(S): There is a statistically significant decrease in the percentage of NK cells, and helper and cytotoxic lymphocytes that produced IFN-gamma in pregnant women when compared with women in the follicular phase. There is also a statistically significant decrease in the percentage of helper lymphocytes producing IL-2 in pregnant women compared with nonpregnant women. CONCLUSION(S): We found a decrease in type 1 cytokine production with no change in type 2 cytokine production after in vitro stimulation of "pregnant" NK cells and lymphocytes as compared with "nonpregnant" NK cells and lymphocytes. We suggest that NK cell and lymphocyte response are shifted away from a type 1 immune response during pregnancy.     

Tumor Lymphocytes in Patients with Advanced Ovarian Cancer: Changes duringin VitroCulture and Implications for Immunotherapy

Tumor specimens and ascites of patients with advanced ovarian cancer were utilized to obtain both primary ovarian carcinoma cell cultures and lymphocytes: tumor-infiltrating lymphocytes (TILs) from solid tumor tissue and tumor-associated lymphocytes (TALs) from peritoneal fluid. Tumor lymphocytes were grown in coculture with autologous tumor cells and recombinant human IL-2 (rhIL-2) for up to 4 weeks and at weekly intervals these were examined with respect to phenotype and cytotoxicity. The phenotype was studied using flow cytometry for a variety of human immunocompetent cell surface markers (CD3, CD4 CD8, CD16, CD56, TCRαβ, TCRγδ). Cytotoxicity was investigated using 4-hr⁵¹Cr-release assays with the primary ovarian carcinoma cell cultures and the K562 cell line as target cells. The tumor lymphocytes did not demonstrate any obvious trend in phenotype changes during culture, although for different cultures a large range was noted for the various lymphocyte populations studied. Cytotoxicity against both autologous and allogeneic targets declined with culture length for the majority (6/7) of the lymphocyte cell lines tested (greatest at 1 week and least at 3 weeks). These initial results indicate that anin vitronon-MHC-restricted cytotoxic function of peritoneal lymphocytes can be effectively activated with IL-2 and autologous tumor cells. However, if activated lymphocytes are to be employed as a form of immunotherapy, they should be given within the first week of culture for maximum cytotoxic effect.