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The chief impediment to the precise biochemical identification of transfer factor and its mechanism of action has been the lack of a reproducible in vitro assay. We now report on a method by which dialysates containing transfer factor of proven in vivo potency can convert nonimmune lymphocytes to immune responsiveness in vitro, as reflected by antigen-triggered lymphocyte proliferation. However, "water-dialyzed transfer factor" (TF(D)) prepared for in vivo use by the conventional method of dialysis against large volumes of water exhibits diminished activity in vitro and is frequently toxic to lymphocyte cultures. This problem can be avoided by dialysis of transfer factor into tissue culture medium. When this precaution is taken, such "media-dialyzed transfer factor" (TF(DM)) causes nonimmune lymphocytes to respond to antigen by an increment of thymidine incorporation that ranges from 2 to 25 times that of such cells cultured with antigen alone. This response is generally observed only in the presence of those antigens to which the TF(DM) donor expresses delayed cutaneous reactivity and is distinguishable from nonspecific adjuvant effects.

Since it is well established that cellular immunity plays a role in the defense against melanoma, the morphologic aspects of this reaction warranted investigation. Accordingly, peripheral blood mononuclear cells obtained from healthy donors were incubated with human melanoma cells for 1 to 24 hours to examine, on the ultrastructural level, the cellular interaction that eventuates in cytolysis of the tumor cells. Within 1 hour of incubation, monocytes and lymphocytes were seen attached to approximately 40 per cent of the melanoma cells with marked interdigitation of cellular processes. After 4 hours of incubation, the percentage of tumor cells with attached leukocytes remained the same, but 2 to 9 per cent of the melanoma cells showed interiorized lymphocytes when kept in suspension, 10 to 25 per cent when maintained in culture dishes. Erythrocytes or fixed lymphocytes were not taken up by the melanoma cells nor were living lymphocytes seen in fibroblasts or endothelial cells which served as controls for the neoplastic cell lines. Thus, melanoma cells did not prove to be randomly phagocytic, and the interiorization displayed by lymphocytes--a process called emperipolesis--appears to be selective. It is postulated that emperipolesis may enhance the tumoricidal effect exerted by cytotoxic lymphocytes on melanoma cells.

Fifteen patients with acquired immune deficiency syndrome (AIDS) and opportunistic infection, were randomized to receive treatment with either thymostimulin (TP-1) at 1 mg/kg for 14 days then weekly for 12 weeks or placebo. The objectives of this study were to evaluate the toxicity of TP-1 in this patient population and to make observations on clinical response as measured by time to second opportunistic infection (OI) and changes in laboratory parameters of immune function. The study demonstrates that TP-1 can be administered safely. There were no differences, however, in time to second OI or overall survival between patient groups. In addition, no change in the immune function could be detected in patients receiving thymostimulin.

A large kindred is reported in which 21 members are balanced t(14q22q) carriers. The components of the translocation were identified by autoradiography and G-banding. With the exception of the index case, who was retarded, all of the carriers were phenotypically normal. The segregation pattern of the translocation chromosome was determined in two complete generations. All eight of the progeny in one generation were balanced carriers, and the carrier father of this generation may have been homozygous for the t(14q22q) chromosome. Segregation in the next generation was closer to the expected 1:1 ratio of carrier to non-carrier, the ratio being 11:13.

Tuberculin-sensitive human lymphocytes cultured for 36 hours with tuberculin elaborate a soluble material which causes nonsensitive lymphocytes to respond to tuberculin in vitro by transformation and proliferation.

When sensitive lymphocytes are cultured with the appropriate antigen, lymphoblasts appear after 24-48 hr of incubation and the number of these increases steadily from the 2nd to the 6th or 7th day. Our problem was to discover, at a cellular level, how this increase takes place; whether it is a massive response of many cells, stepwise recruitment of cells into the lymphoblast class, or simply repeated division of a few cells to form clones. In these experiments lymphocytes were incubated with antigen in culture tubes for 2-4 days and then a few cells, usually less than 200, were transferred to special microchambers for further culture. In these microchambers the cells could be viewed continually with a microscope and their fate recorded over the next 3-5 days by time-lapse cinemicrography. Examination of the film produced in this way showed that lymphoblasts divided and redivided to produce clones of 64 cells or more. It was possible to measure generation times from the film for 301 cells; the majority were between 8 and 13 hr but the range was 7.5-38.0 hr. There was no clear difference between generation times of human lymphocytes stimulated with tuberculin, streptokinase-streptodrnase, extract of the American pokeweed, or in the mixed leukocyte reaction. Similar times were also found for rat cells in the mixed leukocyte reaction. While these observations show that clonal proliferation does occur and could reasonably account for all the increase of lymphoblasts in lymphocyte cultures, the experiments, because of their design, do not exclude the possibility that other mechanisms such as recruitment may play a role as well, particularly during the first 48 hr after contact between sensitive cells and antigens.

1. 19 strains of non-hemolytic hemophilic bacilli were studied. 17 required the addition of V and X growth accessory factors to their media, 2 required the addition of only V. 2. Of 15 strains of hemolytic hemophilic bacilli examined, 10 were found to require the addition of only V to their media, 3 the addition of V and X in the form of yeast extract and hematin, and 2 the addition of accessory growth factors in the form of blood. 3. In media to which neither V nor X had been added true symbiosis was found to occur on growing B. hemoglobinophilus canis, requiring the addition of X, with B. parainfluenzae, requiring the addition of V, or with hemolytic strains of bacilli, requiring the addition of only V.