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Biomedical subjects

A Misefari

Publications and source records attributed to A Misefari.

15 recordsLinked to original sources
PubMed1991

Prostaglandin E2-induced inhibition of the in vitro immune response by SRBC-stimulated human lymphocytes.

Exogenous PGE2 strongly inhibits the response of human lymphocyte cultures to SRBC. This effect is mediated through a T cell inhibition since non-T cells are not significantly affected. Indomethacin, which inhibits in this system lymphocyte endogenous PGE2 synthesis increases the in vitro immune response. The effect of indomethacin is overcame by exogenous PGE2. These data may be relevant for explaining the immunomodulatory role of PGE2 following antigen challenge.

Animals↗
PubMed1990

Senile dementia, Alzheimer type: a distinct entity in the immunosenescence?

Since previous data have provided conflicting results on immunoresponsiveness in senile dementia, Alzheimer type (SDAT), we evaluated the immune function in groups of SDAT patients and aged and young donors. In comparison to the younger subjects, SDAT and aged subjects did not exhibit significant differences in lymphocyte surface markers. Both groups of aged donors showed decreased B cell polyclonal responsiveness in a nonspecific T cell-driven B lymphocyte differentiation system. The use of an antigen-specific induction assay revealed an imbalance of T helper (Th) or T suppressor function in the elderly, while SDAT individuals were characterized by decreased Th activity. At the same time, aged individuals manifested an impairment of leukocyte-inhibiting factor (LIF) and lymphocyte-derived chemotactic factor production; a selective deficit of LIF release was seen in SDAT. Finally, elderly individuals displayed a decline of polymorphonuclear cell (PMN)-mediated functions and monocyte phagocytosis; only a decrease in PMN response was observed in SDAT. These results reveal discrepancies in impaired immune responses between SDAT and aging.

Adult↗
PubMed1989

Humoral and cellular immune responses to Salmonella typhi in patients with typhoid fever.

Humoral and cellular immune responses to Salmonella typhi have been studied in nine children with typhoid fever. By using dot immunobinding assay, anti-O-polysaccharide chain and antilipid A antibody titers have been evaluated during the course of the disease. Anti-O-polysaccharide chain antibody titers are lower at the first week and increase up to the third week of the infection. On the other hand, antilipid A antibody levels, which are already higher at the beginning of the disease, progressively augment during the following weeks. Concerning cellular immunity to S. typhi, antibacterial activity mediated by typhoid peripheral mononuclear cells has been determined. Results show this function to be depressed in the initial phase of typhoid, increasing with the time. Together, these data bring new insight on immunity in typhoid patients.

Antibodies, Bacterial↗
PubMed1989

Effects of substance P on the spontaneous binding of Salmonella minnesota R345 (Rb) to human peripheral blood lymphocytes.

The effects of substance P (SP) on Salmonella minnesota R345 (Rb) binding to human peripheral blood lymphocytes (PBL) were evaluated. Two parameters of bacterial cytoadherence were considered, namely the binding lymphocytes (BL) and the number of bound-bacteria/lymphocyte (BB). The results showed that SP inhibits both BL and BB in a significant manner. Furthermore, distribution of Salmonella binding to CD4+ and CD8+ lymphocytes was studied following SP pretreatment of lymphoid cells. This neuropeptide is able to hamper the bacterial cytoadherence to both T-cell subpopulations and, in particular, the inhibitory effect on the T-suppressor/cytotoxic subset was more pronounced. These findings are discussed in terms of SP intervention in the mechanism of host protection against invading microorganisms.

Antigens, CD↗
PubMed1989

Effect of prostaglandin E2 on pokeweed mitogen-activated human lymphocyte cultures.

It is shown that a short incubation of peripheral human lymphocytes with PGE2 is able to reduce the B cell differentiation induced by PWM. The target of PGE2 action appears to belong to T lymphocytes, since the treatment of non-T cells is uneffective in reducing the immune response. Both OKT4+ and OKT8+ subsets are sensitive to PGE2. Data concerning the role of endogenous as well as exogenous PGE2 either on unfractionated or fractionated OKT4+, OKT8+ and non-T lymphocytes are also discussed. The PGE2 inhibition on immunoglobulin synthesis in PWM-stimulated cultures seems to be mediated by a complex effect on both the T cell subsets.

Antibody-Producing Cells↗
PubMed1988

Depression by Fc gamma receptor ligands of SRBC-induced IgM-PFC generation in human blood mononuclear cell cultures.

A tissue-culture system to stimulate human peripheral blood mononuclear cells (PBMC) has been employed in which IgM plaque-forming cell (IgM PFC) generation in response to sheep erythrocytes (SRBC) is dependent on macrophages and T suppressor and helper lymphocytes. In this system PBMC from normal subjects give IgM PFC responses ranging from 26 to 938 PFC/culture. Heat-aggregated human IgG or immune complexes present for the duration of culture induce a significant depression of PFC. Unaggregated IgG has no effect on the response or only a moderate stimulatory effect at the highest dose. The results of these experiments are compatible with previous results in a murine system, which indicated that Fc gamma receptor-positive (Fc gamma R+) cells in the suppressor subset are the target for aggregated IgG and induce depression of the PFC response. A similar mechanism may be operating in the human system described here, although the target cell has not been identified. These results may reflect a mechanism of immunomodulation dependent on interaction of Fc receptor (FcR) ligands with FcR, which may play a role in the pathogenesis of immune complex disorders.

Antibody-Producing Cells↗
PubMed1988

Mononuclear cells from rheumatoid arthritis patients exhibit a depressed IgM response to sheep erythrocyte stimulation in vitro.

Human peripheral blood mononuclear cells when cultured for the short term (11 days) produce an optimal IgM plaque-forming cell (PFC) response to sheep erythrocytes, which is dependent on macrophages and T suppressor and helper lymphocytes. With this system we have investigated the PFC response of individuals with rheumatoid arthritis and compared this to the response of normal sex- and age-matched controls and of patients with osteoarthritis. The response of rheumatoid arthritis patients was significantly lower than that of subjects in the other two categories.

Animals↗
PubMedDate not supplied

[The antistreptolysin activity of lysozyme].

The action of O-streptolysin on rabbit red corpuscles is inhibited by lysozyme, whereas the enzyme has no effect on termostable cytotoxic fraction of the toxin. Moreover little amounts of lysozyme canhance the anti-streptolysinic titers of human immune sera. These findings and the relationship between the biological activities of O-streptolysin are discussed.

Animals↗