Human peripheral Nullymphocytes: ultrastructural aspects of the "K" cell effect against a melanoma target cell

A null cell fraction was isolated from human peripheral blood by Ficoll density gradient centrifugation followed by removal of mononuclear phagocytes, passage through Ig-antiIg columns and sedimentation of E-rosette forming T cells. In contrast to the T cell fraction in the Null cell population exhibited cytotoxic activity against antibody-sensitized human melanoma target cells (ADCC reaction). This activity could be attributed to a low affinity Fc-receptor bearing cells present in the Null cell preparation. At the ultrastructural level in 2 h ADCC reaction most tumor cells were surrounded by up to 10 lymphoid cells which showed narrow junctions with parallel plasma membranes and local evaginations of lymphoid cells into recessus of the target melanoma cells. The mononuclear cell type found in close contact with the antibody-sensitized target cells had the following morphological criteria: 8 to 10 mu diameter, irregular nucleus, discrete rough endoplasmic reticulum, isolated ribosomes, cytoplasmic organelles concentrated under a ruffling membrane in the contact area with the tumor cell.

[Urinary evaluation of 5-S-cysteinyldopa and seric evaluation of IgG4 subclass during follow-up of 27 primitive malignant melanomas (author's transl)]

27 patients with SSM or NM level IV and V have been submitted to a monthly evaluation of their level of 5-S-cysteinyldopa in the urine and IgG4 subclass in their sera. For 5 patients who entered the stage II of their disease during the follow-up, 3 had elevation of the 5S and 5 had large variations of IgG4. On 21 patients in clinical remission, 10 had conjunctly an increase of 5S and variations of IgG4. The predictional value of these tests is discussed.

[Melanocytes in epiloia; ultrastructural aspects (about 7 cases) (author's transl)]

Hypopigmented macules of epiloia have been studied by photonic and electron microscopy in 7 cases. The number of melanocytes was not decreased but these cells were hypotrophic and had a low tyrosinae activity. The melanosomes were smaller in size and their maturation rate was greatly reduced; many abnormal round and granular melanosomes, phaeomelanosome-like, were observed. In one case, such abnormal melanocytes were also occasionally found in normally pigmented control skin.

[Replication of immune RNA by human lymphoblastoid cells]

Animal immune RNA used for the induction of the human lymphoblastoid cell line LDV/7, induces the appearance of receptor sites on the surface of these cells and the synthesis of specific immunoglobulins which are liberated into the culture medium. Furthermore, RNA has been extracted from these cells, which possesses the same properties of specific cytotoxicity as the RNA used for induction. It is supposed that the immune RNA derepresses specific genes on the genome of the induced cells.

[IgG levels in the sera of melanoma patients (author's transl)]

397 sera from 185 melanoma patients have been tested. We classified our subjects into three groups, according to the stage of disease. An alteration of the level of IgG4 subclass was found and related to the extension of the disease. The percentage of abnormalities was more frequent in stage II and III (55 p. 100 and 53 p. 100) than in stage I (19 p. 100). High titers of IgG 4 subclass were essentially detected in advanced disease. The biological significance is discussed.

[IgG levels in the sera of melanoma patients (author's transl)]

397 sera from 185 melanoma patients have been tested. We classified our subjects into three groups, according to the stage of disease. An alteration of the level of IgG 4 sub-class was found and related to the extension of the disease. The percentage of abnormalities was more frequent in stage II and III (55 p. 100 and 53 p. 100) than in stage I (19 p. 100). High titers of IgG 4 subclass were essentially detected in advanced disease. The biological significance is discussed.

IgG4 subclass in malignant melanoma

Three hundred and ninety-seven sera from 185 melanoma patients were studied. These sera were classified into three groups according to stage of disease. An alteration in the level of the IgG4 subclass was found. It was related to the dissemination of disease. The percentage of abnormalities (either increased or decreased levels of IgG4) was more frequent in patients with stage II and III diseases (55 and 53%, respectively) than in patients with stage I(19%). The higher frequencies of high titers of IgG4 were essentially detected in advanced disease. The biologic significance of the increase of IgG4 in melanoma remains obscure. The increase may be related to the development of facilitating antibodies of the IgG4 subclass.

[IgG subclasses in malignant melanoma]

The 397 sera from 185 melanoma patients have been studied and classified in three groups according to the stage of disease. Our findings revealed an alteration of the level of IgG4 subclass which is related to the dissemination of disease. The percentage of abnormalities (either increased or decreased levels of IgG4) was more frequent in stage II and III (55% and 53% respectively) than in stage I (19%), The higher frequencies of high titers of IgG4 were essentially detected in advanced disease. The biological significance of the increase of IgG4 in melanoma remains obscure. It may be related to the development of facilitating antibodies of IgG4 subclass.

Ultrastructure and virus particles of L1210/Mes. A hamster-adapted murine leukemia

The ultrastructural features and virus particle content of L1210/Mes., the hamster-adapted strain of murine leukemia L1210, has been studied in cheek pouch tumors and cell cultures. In comparison with the parental murine tumor in culture, L1210/Mes. has experienced certain morphologic alterations, such as a striking increase in cell size, enlarged and more bizarre nuclei, and an increase in the number of lysosome-related structures. Type A (intracytoplasmic and intracisternal) and type C virus particles could be demonstrated in cell cultures of murine leukemia L1210, and in cheek pouch grafts and cell cultures of L1210/Mes. No. "H" (or "R") hamster-associated virus particles, however, could be distinguished in L1210/Mes. tumors or in vitro cultivated cells. It appears that a murine lymphoma capable of serial propagation in a xenogeneic host permits the replication of virus particles structurally indistinguishable from those indigenous to it.

Cell-mediate cytotoxicity in vitro of human lymphocytes against a tissue culture melanoma cell line (igr3)

Purified peripheral blood lymphocytes from 13 healthy donors, 6 melanoma patients and 1 halo nevus patient were tested for cytotoxic activity against an allogeneic melanoma cell line (IGR3) in, at least, one of the following assays: cell-mediated cytotoxicity (ADCC) and microcytotoxicity assays (ma). The lymphocytes were isolated by Ficoll-Triosil gradient centrifugation (fraction F) followed by removal of iron-phagocytosing and adherent cells (fraction FFF) and by subsequent passage through anti-IgG columns (fraction FFF-C). Leukocytes of each fraction were identified by different methods including morphology, rosette-formation, phagocytic activity, and membrane fluorescence. CMC activity paralled ADCC activity at a log lower level of sensitivity. In both assays lymphocytes of fractions F and FFF had the highest activity, whereas in fraction FFF-C cytotoxicity was strongly reduced. In all three lymphocyte fractions CMC and ADCC activity could be blocked by preincubation of the effector cells in aggregated IgG. Furthermore, depletion of E rosette-forming lymphocytes slightly increased ADCC and CMC activity, whereas depletion of EA and EAC rosette-forming lymphocytes strongly decreased it. Our results therefore indicate that in both CMC and ADCC assays, non-adherent, non-phagocytic Fc receptor-bearing lymphocytes ("K" cells) were the active cytotoxic cells. In MA, on the other hand, mononuclear phagocytes seemed to be the most active cell population. So far no significant difference was observed in CMC, ADCC, and MA between control persons and melanoma patients

Cell-Mediated Cytotoxicity in Vitro of Human Lymphocytes against a Tissue Culture Melanoma Cell Line (IGR3)

Purified peripheral blood lymphocytes from 13 healthy donors, 6 melanoma patients and 1 halo nevus patient were tested for cytotoxic activity against an allogeneic melanoma cell line (IGR3) in, at least, one of the following assays: cell-mediated cytotoxicity (CMC), antibody-dependent cellular cytotoxicity (ADCC) and microcytotoxicity assays (MA). The lymphocytes were isolated by Ficoll-Triosil gradient centrifugation (fraction F) followed by removal of iron-phagocytosing and adherent cells (fraction FFF) and by subsequent passage through anti-IgG columns (fraction FFF-C). Leukocytes of each fraction were identified by different methods including morphology, rosetteformation, phagocytic activity, and membrane fluorescence.

CMC activity paralled ADCC activity at a log lower level of sensitivity. In both assays lymphocytes of fractions F and FFF had the highest activity, whereas in fraction FFF-C cytotoxicity was strongly reduced. In all three lymphocyte fractions CMC and ADCC activity could be blocked by preincubation of the effector cells in aggregated IgG. Furthermore, depletion of E rosette-forming lymphocytes slightly increased ADCC and CMC activity, whereas depletion of EA and EAC rosette-forming lymphocytes strongly decreased it. Our results therefore indicate that in both CMC and ADCC assays, non-adherent, non-phagocytic Fc receptor-bearing lymphocytes (“K” cells) were the active cytotoxic cells. In MA, on the other hand, mononuclear phagocytes seemed to be the most active cell population. So far no significant difference was observed in CMC, ADCC, and MA between control persons and melanoma patients.

Branched tubular structures in human malignant melanoma

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