Biological effects of conjugated linoleic acids supplementation.

Conjugated linoleic acids (CLA) are a group of polyunsaturated fatty acids (PUFA) with a single pair of conjugated double bonds. The major natural CLA isomer is 18:2 cis-9, trans-11 (c9, t11) linoleic acid, or rumenic acid (RA). Chemically synthesized CLA is also available, mostly as a mixture of RA and 18:2 trans-10, cis-12 (t10, c12) isomers in equal amounts (50:50). Consumption of ruminant meat (beef and lamb) and dairy products (milk and cheese) is the main source of dietary exposure to CLA. Despite numerous studies on animal and human models (tumorigenesis, obesity, immune response) it has not been established whether additional supplementation of CLA is of benefit. Moreover, some studies, conducted both in animals and in humans, reveal that CLA isomers may induce insulin resistance. Presently, balanced diet rich in CLA from natural sources is recommended. The purpose of this review was to sum up the results available in the literature.

Spontaneous production of lymphocyte migration inhibitory factor (sLyMIF) by T and B lymphocytes from peripheral rabbit blood.

Nonstimulated 24 h cultures of lymphocytes from rabbit peripheral blood, as well as isolated rabbit T and B lymphocytes release into the culture medium a factor inhibiting migration of T and B lymphocytes (LyMIF). Synthesis of the factor can be blocked by puromycin. The stimulatory factor for B lymphocyte migration (LyMSF) can also be produced in T lymphocyte cultures. The synthesis of both factors occurs in suspensions containing monocytes, as well as in those lacking monocytes.

Inhibition or stimulation of immediate, spontaneous rosette formation at various SRBC:lymphocyte ratios.

The active rosette-forming cell (ARFC) percentage was investigated in a group of 100 persons, consisting of 50 healthy blood donors, 30 cancer patients (CA), and 20 patients suffering from rheumatoid arthritis (RA). The test was repeatedly performed using five SRBC:lymphocyte ratios: 10:1, 20:1, 5-:1, 100:1, and 200:1. In 18% of healthy donors and 30-40% of cancer patients, contrary to the remaining persons no relation between ARFC percentage and the SRBC:lymphocyte ratio was found. The "optimal" SRBC:lymphocyte ratio, varied from group to group and was 20:1 for most of RA patients, 50:1 for most of CA patients and 100:1 for most of healthy people. Sometimes, at higher SRBC:lymphocyte ratios a significant lowering of the ARFC percentage was found in relation to the optimal proportion for a given person, and this was observed for 200:1 ratio in 68% of healthy people, 54% of cancer patients and 90% of patients with RA. It is suggested, that ARFC test should be always performed at least in these three SRBC:lymphocyte ratios. Inhibition or stimulation of rosette formation by supernatant fluids of lymphocytes and SRBC suggest that SRBC release substances, which can directly or indirectly inhibit or stimulate rosette formation.

The immunosuppressive effect of concanvalin A. III. Influence on the survival time of skin allografts in mice.

The influence of Con-A on the survival time of skin grafts in mice was examined. F1 mice (BALB/c X DBA/2) were the skin donors and C57BL X C3H were the recipients. More than a two-fold prolongation in the survival time of the grafted skin was obtained by a single 100 microgram dose of Con-A given intravenously to mice 24 h prior to grafting. Con-A given in a similar manner three days after grafting did not influence the skin graft. The results obtained substantiate our earlier observations which suggested that Con-A administered prior to an antigen may inhibit the immunological response.

A one-stage test for simultaneous study of migration inhibition factor of peripheral leukocytes (LIF) and migration inhibition factor of mouse spleen cells (MSIF).

A one-stage modification of the test of the migration inhibition is described, which permits stimultaneous study of the factor influencing in vitro migration of peripheral blood leukocytes and mouse spleen cells. The results of this correlate with the results of the two-stage test.

Circulating suppressor cells in aplastic anemia.

In vitro proliferation and differentiation of hematopoietic stem cells was studied in a patient with aplastic anemia. Prior to therapy his peripheral blood contained a very low number of myeloid progenitors but a normal number of cells forming lymphoid colonies. Moreover, peripheral blood lymphocytes of this patient were able to suppress in vitro formation of myeloid colonies but not lymphoid colonies. This suppression effect was found to be sensitive to prednisolone and antithymocytic globulin. Following treatment with prednisolone, during which an apparent hematological recovery was observed, the level of lymphoid progenitors fell, but myeloid committed cells returned to normal and hematopoietic suppression was no longer detectable. These results indicate that cells suppressing hematopoiesis may circulate in the peripheral blood of some patients with aplastic anemia and the detection and testing of suceptibility of these cells to immunosuppressive drugs may be helpful in monitoring treatment and prognosis.

Effect of lipopolysaccharide on the development of cell-mediated immunity to transplantation antigens.

Lipopolysaccharide (LPS) from Escherichia coli administered to allografted mice in a single dose of 20 microgram influenced the development of cell-mediated immunity to skin donor antigens. As an indicator of cell-mediated immunity, donor antigen-induced inhibition of cell migration from spleen explants of allografted animals was used. Cultures of spleen explants were established 16 days after grafting. The antigen-specific inhibition of migration was abolished when LPS was injected either 4 to 2 days before grafting and intensified when LPS was administered on the 2nd day after grafting.

Immunosuppressive effect of concanavalin-A. II. In vivo suppression of cytotoxic lymphocytes generation in alloimmunized mice.

An examination was carried out of the in vivo effect of Concanavalin-A (Con-A) on the induction of secondary cytotoxic response (CL) to allogeneic spleen cells in mice. CL responses were suppressed by one i.v. injection of 200 micrograms of Con-A one day before first or second immunization or two i.v. injections of Con-A, 200 micrograms each, given simultaneously with immunization. Single dose of 200 microgram of Con-A given simultaneously inhibited anamnestic CL response only partially, to the range observed in the primary response.

The effect of uremia and dialysis on cell-mediated immunity.

Delayed-type hypersensitivity to PPD, two types T rosettes as well as lymphokine production were studied in patients with end-stage renal failure maintained on hemodialysis. A significant impairment of skin reactivity and the lowering of the number of T cells were found, while no definite changes of lymphokine production were detected. No conclusive data are obtained as to the role of hemodialysis in reversing of immunologic deficits noted in uremia.

Studies on the human mixed lymphocyte culture. I. The influence of the irradiated autogenic and allogenic lymphocytes on DNA synthesis.

Fourteen patients with chronic renal failure and their prospective living donors were examined. DNA uptake by donors' monocultures, recipients' monocultures and mixed cultures was measured. The influence of X-ray treated cells on proliferative capacity of untreated cells in these three types of cultures was studied. The suppressing effect of irradiated cells was found in 52%, the enhancing one in 7% and no effect was observed in 41% of lymphocyte cultures. The possible explanations of the findings are discussed.

Studies on the human mixed lymphocyte culture. II. Comparison of one-way and two-way test performed on lymphocytes of patients with end-stage renal failure and their prospective living donors.

The results of DNA synthesis in human one-way and two-way mixed lymphocyte cultures were compared. Twenty patients with chronic renal failure and their twenty six prospective living donors were investigated. Statistical correlation was found on the level alpha = 0.01 between the stimulation index value calculated for one-way and two-way technique. Two-way MLC, the rapid and simple and simple assay detecting lymphocyte activation is a very useful tissue typing test.

The appearance of factors influencing migration of lymphocytes (LyMIF and LyMSF) in rabbit mixed lymphocyte cultures.

In vitro migration of mixtures of peripheral blood lymphocytes derived from 26 pairs of rabbits was significantly suppressed in 73% of cultures, significantly enhanced in 4% and unchanged in 23%, as compared to the corresponding monocultures. Sensitization of 26 rabbits by kidney graft resulted in more frequent appearance of migration enhancing factor. Six days after grafting 54% of donor-recipient mixed cultures showed enhancement of migration, 31% inhibition and 15% no effect. No enhancing factors were produced on the 9th day.

The effect of ATG treatment on LyMIF and LyMSF production in mixed lymphocyte cultures of rabbits after renal allotransplantation.

Rabbit lymphocytes, settled up in microcappillary tubes migrate into culture medium. In the previous communication we have shown that migration of mixture of lymphocytes derived from two blood donors was significantly inferior in 73% of cultures as compared to the corresponding monocultures. 4% of mixed cultures exhibited significant enhancement of migration and in 23% no effects were seen. Use of lymphocytes from rabbits 4-6 days after kidney allotransplantation and their corresponding donors resulted in conversion of this ratio. Percentage of cultures exhibiting enhancement of migration (production LyMSF) rose to 39, 46% of cultures were inhibited (produced LyMIF) and 15% did not show any significant effect. Treatment of kidney recipients with ATG exerted strong inhibitory effect on the appearance of LyMSF and on the appearance of LyMIF in mixed cultures. These results suggested that LyMIF and LyMSF were produced by separate cell populations.

The effect of varying SRBC/lymphocyte ratio on T cell rosette formation.

To determine the effect of varying the SRBC/lymphocyte ratio on rosette formation, rosettes were formed at SRBC/lymphocyte ratios ranging from 10 to 200. To assess the significance of the time of incubation, duplicate samples were mixed at various SRBC to lymphocyte ratios and the percentage of rosette-forming lymphocytes was determined immediately or after an 1-hour incubation at 4 degrees C. The results of five experiments revealed the highly statistically significant difference between the percentage of rosette-forming cells in tests performed with (higher number of RFC) and without (lower number of RFC) incubation, in all SRBC/lymphocyte ratios. On the other hand, ratio of SRBC to lymphocytes influenced significantly the results obtained in both types of tests, this effect was more pronounced in test performed with 1-hour incubation. Optimal SRBC/lymphocyte ratios for both tests were 100:1 (31% RFC without incubation and 53.4% of RFC after 1-hour incubation.

Fractionation of human T lymphocytes on the basis of their high, medium and low SRBC-rosette-forming affinity: efficiency of the method.

Under optimal saturating conditions at SRBC/lymphocyte ratio 100:1 26 +/- 1.2% of human peripheral blood lymphocytes isolated from defibrinated blood form rosettes without incubation, 48 +/- 1.8% after 1-hour, 68 +/- 1.7% after 2 hours incubation at 4 degrees C. According to this, human peripheral T lymphocytes may be subdivided into at least three fractions on the basis of their affinity to SRBC. We called these fractions AFRC (no incubation), C1 RFC (1-hour incubation in cold after removing ARFC fraction) and C2RFC (2-hour incubation in cold after removing ARFC and C1RFC fractions). All the three fractions may be separated by repeated rosetting followed by Ficoll-Uropoculine gradient centrifugation. The purity and viability of T lymphocytes yielded from particular fractions was high. Effective yield of lymphocytes varied between the particular fractions ranging between 100% (for AFRC) and 30% (for C2RFC).