Induction of activated natural killer cells from murine spleen cells primed in vivo and subsequently challenged in vitro with the streptococcal preparation OK432

Abstract

The present study shows that natural killer cell-mediated cytotoxicity of BALB/c mouse spleen cells to syngeneic tumor cells was augmented by in vivo priming or in vitro stimulation with the streptococcal preparation OK432. The augmentation of spleen cell cytotoxicity to syngeneic tumor cells by in vivo priming alone with OK432 was lower than that obtained by in vitro stimulation alone with OK432. When the murine spleen cells primed in vivo with OK432 were rechallenged in vitro with OK432 at various intervals, the natural cytotoxicity was more strongly enhanced than that seen with in vitro stimulation alone. The cell surface phenotype of killer cells activated with OK432 was Thy 1+ and asialo GM1+, suggesting the activated natural killer cell. Next, mice were transplanted with syngeneic colon adenocarcinoma cells, and primed in vivo with OK432. These spleen cells were subsequently challenged in vitro with OK432. These spleen cells displayed a strong cytotoxic activity not only to the transplanted adenocarcinoma cells but also to other syngeneic tumor cells.

Role of interleukin-2 and interferon-? in induction of activated natural killer cells from mice primed in vivo and subsequently challenged in vitro with the streptococcal preparation OK432

“…Mice were given subcutaneous injections of 0.1 mg OK432 for in vivo priming. On days 4 -8 after priming in vivo with OK432, spleen cells were harvested and suspended in complete medium, because stronger augmentation of cytotoxic activity was seen against NK-sensitire and -resistant targets on days 4-14, as compared with that induced by in vitro OK432 challenge alone [45]. For in vitro challenge, spleen cells at a concentration of 2.5 x 106/ml in complete medium were incubated with an optimal dose of OK432 (12.5 p~g) for various incubation times at 37°C in a humidified 5% CO2 atmosphere, be-cause this dose of OK432 can maximally augment the NK activity [43].…”

“…The SP2 syngeneic myeloma cells and YAC-1 allogeneic lymphoma cells were used as NK-sensitive targets [45], and the syngeneic C26 colon adenocarcinoma cells were used as NK-resistant targets [45].…”

“…There are many reports that natural killer (NK) cell activity is augmented by OK432 in vivo or in vitro [2,26,38,41]. We have reported that in vivo priming and in vitro rechallenging with OK432 maximally enhances natural cytotoxicity of the murine spleen ceils, and that the surface phenotype of killer ceils activated with OK432 is Thy-1 + and asialo-GMl +, suggesting the activation of N K cells (OK-NK cells) [45].…”

Fibronectin promotes the proliferation of cytotoxic T lymphocytes generated from cancer patients

“…Tumour cells depleted of lymphoid cells were collected from the bottom and from the 25% interface, and were then washed and suspended in complete medium. The 51Cr-release assays (CRA) were performed to assess killer cell cytotoxicity, as described Yamaue et al, 1987Yamaue et al, , 1989 Since we have been culturing CTLs stimulated by 10 pg ml-' immobilised anti-CD3 MAb and 250 IU ml-' IL-2 for adoptive immunotherapy of cancer patients (Tani et al, 1995), we examined the effect of immobilised FN on CTLs stimulated by 10 ,ug ml-' immobilised anti-CD3 MAb and 250 IU ml-' IL-2 (Table II). The enhancement of proliferation of CTLs was observed by immobilised FN at concentrations of 2 -50 pg ml -' (P < 0.05).…”

The antitumour activity of the interferon inducer bropirimine is partially mediated by endogenous tumour necrosis factor α

“…So far, endogenous-exogenous therapy has been performed using the streptococcal preparation OK432 as the TNFc(-inducing agent [26]. Like bropirimine, OK432 causes the release of TNFo~ [23] and it increases macrophage [23], NK cell, [33] and large granular lymphocyte cytotoxicity [29]. It also induces the release of interferon [22].…”