Richard A. Adams

The question of stemlines in human acute leukemia: Comparison of cells isolated in vitro and in vivo from a patient with acute lymphoblastic leukemia☆

Abstract Mononuclear, lymphoblastoid (CCRF-SB) cells isolated in suspension culture from the peripheral blood buffy coat of a child with acute lymphoblastic leukemia have been non-tumorigenic in untreated neonatal Syrian hamsters. This observation is in contrast to the previously reported serial transplantability of H-SB2, a tumor produced in newborn hamsters by the direct implantation of buffy coat cells from the identical blood specimen. Cells of the CCRF-SB culture are, however, tumorigenic in newborn hamsters treated with anti-hamster thymus lymphocyte serum (ALS). Unlike H-SB2, the tumor (H-SB9) produced in hamsters by implantation of the CCRF-SB cells is dependent upon treatment of the host with ALS for transplantation, does not undergo spontaneous conversion to leukemia in the hamster host, and actively synthesizes human immunoglobulins. These, together with karyotypic and certain biochemical differences (described elsewhere) raise the possibility of the existence of different “stemlines” in this patient with acute lymphoblastic leukemia. However, the available evidence suggests that only the H-SB2 cell population represents a leukemic “stemline”. The CCRF-SB cell population more closely resembles previously described lymphoid cells derived from the peripheral blood of patients with infectious mononucleosis.

Malignant potential of a cell line isolated from the peripheral blood in infectious mononucleosis

A cell line (designated CCRF‐RKB) has been isolated in continuous (spinner) suspension culture from the peripheral blood of a patient with infectious mononucleosis. Injection of the cells into neonatal Syrian hamsters resulted in the growth of malignant tumor. In neonatal hamsters treated with antihamster thymus serum (ALS), the tumors were serially transplantable and metastatic. In the first few passages of the tumor grown in ALS‐treated neonates, human IgG and IgM were detected in the circulation of the tumor‐bearing hamsters. In later passages, 2 tumor sublines developed, one which acquired the capacity to grow without ALS and another which disseminated sufficient numbers of tumor cells into the blood to approach leukemic counts and to enable implanted whole blood to produce tumor. Both tumor sublines killed the host more rapidly than did the parent line. Immunofluorescence methods indicated that the cells of the parent tumor line and both sublines retained human species‐specific antigens at the cell surface and lacked hamster antigens.

Malignant immunoblastoma: immunoglobulin synthesis and the progression to leukemia in heterotransplanted acute lymphoblastic leukemia, chronic lymphatic leukemia, lymphoma, and infectious mononucleosis.

The heterotransplantation of cells from human subjects with overt lymphoid neoplasia or infectious mononucleosis into newborn Syrian hamsters treated with antilymphocyte serum results in serially transplantable malignant tumors. These tumors are composed of cells retaining human species‐specific antigen at the cell surface, and hence represent progeny of the implanted human cells rather than tumor cells induced in the hamster by an oncogenic agent. The tumors appear to fall into two categories on the basis of their behavior in the hamster. Category A consists of tumors derived solely from subjects with acute lymphoblastic leukemia secondary to lymphosarcoma, which in the hamster progress to acute leukemia and apparently do not secrete immunoglobulins. Category B consists of tumors derived from all of the remaining diagnostic categories thus far investigated and from acute lymphoblastic leukemia in remission as well, which in the hamster secrete immunoglobulins of human type and do not progress to acute leukemia. The descriptive term “malignant immunoblastoma” is provisionally proposed for the category B tumors, to emphasize their experimental derivation as well as their relationship to cells of the immunoglobulin‐secreting type. The hypothesis is advanced that the category A acute leukemias and the category B malignant immunoblastomas therefore may be related to T and B lymphocytes, respectively. The oncogenicity in hamsters of directly injected peripheral blood buffy coat cells from subjects with infectious mononucleosis raises the possibility that this lymphoproliferative disease may be a benign, self‐limiting form of lymphoma. These observations with infectious mononucleosis may provide inferential evidence for the existence in man of hostregulatory, cancer‐preventing mechanisms of perhaps substantial importance.

Nutritional requirements of human leukemic cells: Cystine requirements of diploid cell lines and their heteroploid variants☆

Abstract Cultures of human leukemic cells derived from the peripheral blood buffy coats of pediatric patients in whom the presenting lymphoma had progressed to acute lymphoblastic leukemia were studied with respect to their l -cystine requirements in both the diploid and, following serial passage in intact newborn Syrian hamsters, the heteroploid state. With one exception, all of these cultures exhibited an absolute requirement for l -cystine which was independent of state of ploidy and cell population density. The classical methionine-cystine pathway appears to be defective or lacking in these cells, and unlike other kinds of cells, the development of heteroploidy did not effectively de-repress the metabolic pathways concerned with the biosynthesis of cystine. The one exception was the CCRF-SB culture which utilized l -cystathionine for growth, in contrast to the inability of the other cultures so examined to utilize this precursor of l -cystine; including the CCRF-H-SB-2 cells which were derived directly in intact newborn Syrian hamsters by implantation of the same peripheral blood buffy coat specimen from which the CCRF-SB cells were isolated in culture. Unlike the CCRF-H-SB-2 cells (and the others considered herein), the CCRF-SB cells do not implant in intact newborn Syrian hamsters. Whether the difference in their ability to utilize l -cystathionine relates to the fundamental biological distinction suggested by the differences in their heterotransplantability, or merely reflects the divergent development of different stem lines of leukemic cells is unclear at the present time.

Chemotherapy and immunotherapy of three human lymphomas serially transplantable in the neonatal Syrian hamster.

Three lymphomas, serially transplantable in Syrian hamster neonates, have been derived by intraperitoneal implantation of lymphoblasts from the peripheral blood of two pediatric patients with lymphosarcoma that had undergone progression to acute lymphoblastic leukemia. Two of the neoplasms are serially transplantable in normal, untreated Syrian hamster neonates. The third is transplantable only in neonatal hamsters treated with rabbit antiserum to hamster thymus cells, antilymphocyte serum, (ALS). None is transplantable in adult hamsters. These experimental tumors in the hamster neonate have been examined for their responses to chemotherapy, immunotherapy, or both. Agents were administered in a single dose intraperitoneally, 7 days after implantation. Methotrexate more effectively controlled tumor growth than did 6‐MP, prednisone, Cytoxan, vincristine, actinomycin D, or D54 · naponate (listed roughly in decreasing order of effectiveness). An antiserum made in rabbits against the human tumor cells was ineffective when administered at 7 days, but highly inhibitory in the first 1–3 days. Immunization of the mother with tumor cells at 23–75 days before littering prevented tumor growth in neonatally challenged offspring. Treatment of the neonate with spleen cells derived from adult normal or specifically sensitized hamster donors was also effective in inhibiting tumor growth. The data suggest that human lymphoma serially transplantable in the newborn hamster may constitute a system practical for the study of potentially useful chemotherapeutic or immunotherapeutic agents. Such a system might be especially applicable in the study of chemical agents which are active against human cells in vitro but inactive in standard mouse tumor assays in vivo.

IMMUNITY AND SUSCEPTIBILITY TOWARD CHEEK POUCH TRANSPLANTS OF A MOUSE LEUKEMIA.

Intravenous sensitization with spleen or leukemic cells of mice and certain rats immunized Syrian hamsters toward cheek pouch heterografts of a mouse leukemia. By contrast, sensitized hamsters given cortisone became more susceptible to the challenging leukemic graft. Neither response was elicited by sensitization with cells of the guinea pig, Syrian hamster, rabbit, or human being.