The effect of in vitro ã-irradiation on mitogenic responsiveness of murine lymphocytes

The objective of this study was to analyze the proliferative response of BALB/cmice lymphocytes after in vitro irradiation (0.05 to 6 Gy). The capability of irradiatedlymphocytes for proliferating without any stimulation and after activation withspecific T and B cell mitogens has been evaluated. The results show that ionizingradiation significantly inhibits spontaneous cellular proliferation and that induced bymitogens and that variations in the degree of inhibition are found depending on theinducing proliferation mitogens and the dosage applied. The conclusion drawn is thatdifferent lymphocyte populations have different radiosensitivities, being B cells moresensitive to ionizing irradiation than T cells. Besides, the effects of gamma-irradiationvary according to the different subpopulations of T cells or, alternatively, to differentT-dependent activation mechanisms (AU)

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The effect of in vitro gamma-irradiation on mitogenic responsiveness of murine lymphocytes.

The objective of this study was to analyze the proliferative response of BALB/c mice lymphocytes after in vitro irradiation (0.05 to 6 Gy). The capability of irradiated lymphocytes for proliferating without any stimulation and after activation with specific T and B cell mitogens has been evaluated. The results show that ionizing radiation significantly inhibits spontaneous cellular proliferation and that induced by mitogens and that variations in the degree of inhibition are found depending on the inducing proliferation mitogens and the dosage applied. The conclusion drawn is that different lymphocyte populations have different radiosensitivities, being B cells more sensitive to ionizing irradiation than T cells. Besides, the effects of gamma-irradiation vary according to the different subpopulations of T cells or, alternatively, to different T-dependent activation mechanisms.

Effects of nordihydroguaiaretic acid on murine antibody-dependent cellular cytotoxicity.

The purpose of this study was to analyze the effects of nordihydroguaiaretic acid, an inhibitor of the lipoxygenase pathway of arachidonic acid, on antibody-dependent cellular cytotoxicity. Antibody-dependent cellular cytotoxicity mediated by murine spleen cells was significantly inhibited by concentrations of nordihydroguaiaretic acid from 10(-5) to 10(-4) M (1C50 = 2 x 10(-5) M). The inhibitory effect of nordihydroguaiaretic acid was also observed on antibody-dependent cellular cytotoxicity mediated by macrophage-depleted spleen cells as well as isolated macrophages. Nordihydroguaiaretic acid was highly effective when added at the beginning of the assay and was always present throughout the assay, but failed to inhibit the binding of effector and target cells. The inhibition produced by nordihydroguaiaretic acid could not be reversed by leukotriene B4, a 5-lipoxygenase product. These results suggest that arachidonic acid metabolites other than leukotriene B4 are released by different populations of spleen cells to positively regulate important events in the postbinding phase of murine antibody-dependent cellular cytotoxicity.

Changes in total serum IgE concentrations after splenectomy.

In addition to allergic diseases, there are other disorders that can be accompanied by increased levels of total serum IgE. It has been demonstrated that splenectomy can alter the serum concentrations of other immunoglobulins. The aim of this study was to examine the concentrations of total IgE in the serum of patients splenectomized as a result of abdominal trauma but with no associated disease. Our results show that the average concentrations in the serum of patients were significantly higher that in the control group. Furthermore, in a large number of patients, the concentrations were above the normal limit set for the nonatopic Spanish population. These results suggest that splenectomy can alter the regulation of IgE concentrations. Since total IgE is usually determined for diagnostic purposes, it is useful to be aware of this anomaly when dealing with splenectomized patients in order to interpret correctly the laboratory analyses.

[Humoral immunity following splenectomy in adults]. / Inmunidad humoral tras la esplenectomía en el adulto.

Humoral immunity was examined in a population of one hundred adult patients splenectomized after abdominal trauma without associated disease, and the results were compared with those observed in healthy individuals. We found, in addition to the disorders, a large increase in the seric concentration of total IgE, and increased presence of autoantibodies and circulating immunocomplexes. These alterations were not correlated with the asplenia period.

Autoantibodies in splenectomized patients as a consequence of abdominal trauma.

The presence of autoantibodies was examined in 100 adult patients splenectomized because of abdominal trauma and without systemic disease, and the results were compared with those observed in a healthy control group. Thirty-seven percent of the patients studied presented some type of autoantibody. Those observed were antinuclear, anti-smooth muscle and, in 1 case, anti-reticulin. Patients with antinuclear antibodies have no antibodies against native DNA, but in 5 cases, anti-Ro (SS-A) and anti-La (SS-B) antibodies were observed. Rheumatoid factors were also found, but their incidence was similar in patients and controls. The incidence of autoantibodies proved not to be related to either the period of time since splenectomy or to age of the patient; they were observed in patients many years after splenectomy and in individuals of both sexes and all ages. Although the presence of autoantibodies seemed to have no effect on our patients, all of whom were asymptomatic, it is important to be aware of this phenomenon when evaluating the laboratory results obtained from splenectomized patients.

Effects of lipoxygenase and cyclooxygenase inhibitors on murine antibody-dependent cellular cytotoxicity (ADCC).

The purpose of this study was to determine the effects that specific inhibition of arachidonic acid (AA) metabolism has on the antibody-dependent cellular cytotoxicity (ADCC) of murine spleen cells. The action of three inhibitors of the lipoxygenase (LO) pathway--nordihydroguaiaretic acid (NDGA), esculetin (Es), and phenanthroline (Phe)--was compared with that of three inhibitors of the cyclooxygenase (CO) pathway--indomethacin (INDO), acetyl salicylic acid (ASA), and imidazole (IMI). All the LO inhibitors suppressed ADCC function in a dose-dependent manner, but NDGA was the most potent inhibitor of this cytolytic activity. In fact, NDGA inhibited the ADCC function with 97% inhibition at 100 microM, while Phe and Es, at the same concentration, inhibited ADCC by 21% and 19%, respectively. However, CO inhibitors did not markedly affect ADCC function and only some doses of them had a slight, but significant, depressing effect (8-11% inhibition at 0.01-0.1 microM of INDO, 7% inhibition at 400 microM of ASA, and 13% inhibition at 800-1000 microM of IMI). These results suggest the LO pathway of the arachidonic acid metabolism plays an important role in regulating ADCC activity of murine spleen cells and the products of the CO pathway have little effect on ADCC lysis.

Complement, circulating immunocomplexes and autoantibodies after ionizing radiation exposure.

The short- and long-term effects of whole body irradiation by a single dose (4Gy) on some immunological parameters in mice have been studied. The results showed a transitory but significant impairment of classical activity of complement, high incidence of anti nuclear, anti gastric parietal cells and anti smooth muscle autoantibodies, and circulating immunocomplexes in sera on irradiated mice. These immunological changes could be related to complications developed as late manifestations of radiation effects.

Cellular immunity in splenectomized patients.

Delayed hypersensitivity and lymphocyte subsets in a group of adult splenectomized patients after abdominal trauma without associated disease have been studied. The results were compared with those observed in healthy individuals. The results show a decreased cutaneous reaction against extracts of Streptococcus and diphtheria antigens. Moreover, an increase in the number of lymphocytes and monocytes was observed, but the T4/T8 ratio was not affected. The impaired cutaneous response against Streptococcus could be related to post-splenectomy sepsis.