Recovery of immune competence after tumour resection in mice: correlation with loss of suppressor elements

R D Gasocyne,J G Levy,R B Whitney

doi:10.1038/bjc.1978.27

Abstract

Changes in the immune competence and levels of suppressore elements were assessed by mitogen stimulation and in vitro antibody production, after resection of a transplantable sarcoma. Spleen cells from tumour-resected animals were found to have depressed responses to conA as well as to the antigens SRBC and DNP-LPS. This inability to respond was gradually overcome and, by Day 21 after resection, spleen cell competence had returned to normal levels. Suppressor cells isolated from the spleens of tumour-resected animals were capable of suppressing the conA response and PFC response of normal syngeneic spleen cells in vitro. The ability to suppress the conA response of normal cells disappeared by Day 1 after resection, while the ability to suppress the anti-SRBC and anti-DNP PFC response of normal cells disappeared by Day 8 and Day 14 respectively. Serum from tumour-resected mice was also found to be suppressive to the conA response of normal spleen cells. The inhibitory material responsible for suppression eluted with the Ig-containing fraction on Sephadex G-150. This inhibitory material gradually disappeared from the serum of tumour-resected mice and was no longer apparent by Day 14. Therefore, it appeared that the return of normal lymphocyte function after tumour-resection was concomitant with the disappearance of splenic suppressor cells and suppressive serum factor.

Highlights

Summary.-Changes in the immune competence and levels of suppressor elements were assessed by mitogen stimulation and in vitro antibody production, after resection of a transplantable sarcoma
Recent theories have suggested that tumours grow progressively because of the presence of blocking factors, blocking antibodies or antigen-antibody complexes (Baldwin, Price and Robins, 1973; Hellstr6m and Hellstrom, 1970; Gorczynski et al, 1974); because of a defect in the host's immune response, both cellular and humoral; or because of suppressor elements that develop concurrently with tumour growth and actively antagonize the host's response to tumours and other antigens (Kirchner et al, 1974; Whitney and Levy, 1974; Waldmann and Broder, 1977)
Significant of the concanavalin A (conA) response, a significant level of suppression was detected during the first suppressor spleen cells was not detected. 8 days after surgery

Summary

Surgical resection

Resections were carried out 32 days after tumour implantation. At this time, the tumour mass was 3-5-4-5 g. Treatments which remove adherent cells, including passage through nylon wool columns and treatment with carbonyl iron, effectively removed the suppressor tumours. Previous studies in this laboratory had shown that surgical resection of small tumours, from mice in which immune competence had not yet become impaired, did not cause any change of immune status in resected animals in comparison to untreated controls (Levy et at., 1974). It was concluded that the published data) For these reasons, untreated suppressor cell was of the macrophage/ normal animals were used in this study rather monocyte series (Pope et at., 1976). The cells were centrifuged and resuspended in 10 ml of 0.83% NH4Cl

Collection and preparation of serum

In vitro antibody production

Days from

Days Following Resection

DISCUSSION