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Biomedical subjects

A Tagliabue

Publications and source records attributed to A Tagliabue.

At least 145 records · Page 8Linked to original sources
PubMed1978

Refractoriness to migration inhibitory factor of macrophages of LPS nonresponder mouse strains.

The responsiveness to macrophage migration inhibitory factor (MIF) of peritoneal exudate cells (PEC) from the LPS unresponsive C3H/HeJ and C57BL/10ScCR mice was assessed by the indirect agarose microdroplet macrophage migration inhibition assay. No migration inhibition with PEC from C3H/HeJ nor C57BL/10ScCR mice was detected, whereas PEC from both C3H/HeN and C57BL/10Sn mice were significantly inhibited by even a 1/32 dilution of MIF-containing supernatants. Responsiveness to MIF of C3H/HeJ PEC could, however, be induced. In vivo inoculations of Mycobacterium bovis, strain BCG, 7 days before in vitro assay rendered C3H/HeJ PEC responsive to MIF. The lack of responsiveness to MIF by C3H/HeJ PEC appeared related to some form of suppression, since a mixture of PEC from C3H/HeN mice with 10 to 15% PEC from C3H/HeJ mice resulted in undetectable migration inhibition at any MIF dilution. In contrast to the usual lack of responsiveness of their macrophage to MIF, C3H/HeJ mice were able to produce MIK in response to PPD as well as their counterpart C3H/HeN mice after BCG sensitization. These results demonstrate that macrophages from C3H/HeJ and C57BL/10ScCR mice are unable to be inhibited in their in vitro migration of MIF (possibly being directly or indirectly influenced by a suppressor cell), whereas lymphoid cells from at least one of these strains, the C3H/HeJ mice, can produce MIF in response to antigenic stimulation.

Animals↗
PubMed1977

Effect of immunomodulators on effector cells involved in antibody-dependent cellular cytotoxicity: Brief communication.

The effect of four immunomodulators (BCG, Corynebacterium parvum, pyran copolymer, and levamisole) on the cellular arm of antibody-dependent cellular cytotoxicity (ADCC) was investigated in mice with 51Cr-labeled chicken erythrocytes employed as targets. All these drugs, except levamisole, stimulated the effector cells of ADCC in the spleen, but the kinetics of their effect differed. Stimulation of the effector cells of ADCC peaked on day 15 after injection of BCG and C. parvum and on day 7 after injection of pyran, which was less efficient in this respect than the two bacterial immunostimulants. The increase in ADCC activity caused by BCG and C. parvum was eliminated by treatment with carbonyl iron of the splenocyte suspensions.

Animals↗
PubMed1976

Steroid contraceptive agents and immunological reactivity in experimental animals.

The immunodepressive activity of widely employed steroid contraceptive agents (SCA's) was evaluated in mice and rats on various humoral and cell-mediated responses. Three different progestagens (lynestrenol, norethindrone or norethynodrel) were administered in combination with the estrogen mestrahese SCA's could significantly reduce the severity of allergic encephalomyelitis in rats, variations in their capacity to interfere with primary response to sheep erythrocytes in mice and anti-mouse erythrocyte autoantibody formation were found. Treatments employed with these SCA's did not reduce tumor allograft resistance in mice and the anti-sheep erythrocyte response in rats. In addition, otherwise immunosuppressive treatments with these SCA's did not modify the mouse response to a T-independent antigen. The possible clinical significance of these results is discussed.

Animals↗
PubMed1976

A characterization of the immunosuppressive activity of adriamycin and daunomycin on humoral antibody production and tumor allograft rejection.

The effects of adriamycin (AM) and its analog daunomycin (DM) on immunological responsiveness have been investigated in an effort to elucidate whether a differential interaction of the two drugs with the immune system could play a role in the higher antineoplastic activity of AM. It was found that AM induced a greater reduction in the number of antibody-producing cells after primary stimulation with sheep erythrocytes, whereas DM was more suppressive on the secondary response to the same antigen. Primary reactivity to the T-independent antigen S-III was reduced by AM, whereas DM was ineffective in the same conditions even at high doses. In addition, when a tumor allograft model was investigated, DM was significantly more immunosuppressive than was AM administered at equitoxic doses. In contrast, these agents displayed similar activity in reducing bone marrow stem cells and in inhibiting DNA synthesis in this organ. The possibility that the different immunosuppressive capacity of AM and DM contributes to the greater antitumoral activity of the former is advanced.

Animals↗
PubMedDate not supplied

Antibody-dependent cell-mediated antibacterial activity of intestinal lymphocytes with secretory IgA.

Secretory antibodies of the IgA class (sIgA) are thought to have an important role in the defence against bacteria at mucosal surfaces--the level at which the infectious agents first come into contact with the host. However, the mechanism by which sIgA exert their antibacterial activity is still a matter of debate. After the recent discovery of receptors for the Fc portion of IgA (RFc alpha) on lymphocytes, monocytes and granulocytes of human, rabbit, guinea pig and mouse origin, it has been hypothesized that IgA also mediate antibody-dependent cellular cytotoxicity (ADCC). Indeed, ADCC mediated by human leukocytes against bacteria has been demonstrated in the presence of human circulating IgA. As RFc alpha have also been shown to bind sIgA, we decided to investigate whether sIgA could mediate antibacterial ADCC when bound to lymphocytes from the murine gut-associated lymphoid tissues (GALT) which first interact with the invading bacteria. By using Shigella X16 (a hybrid strain between the enteric pathogen Shigella flexneri and Escherichia coli) as target in an in vitro assay that measures cell-mediated antibacterial responses, we found that murine lymphocytes from GALT but not from other tissues are able to exert natural antibacterial activity against Shigella X16, and that sIgA significantly and specifically increase the natural antibacterial activity of GALT lymphocytes from mice and induce antibacterial activity in cells from the spleen, but not from the thymus or popliteal lymph nodes. Thus, we now propose a new role for sIgA in protecting the host against infectious agents at the mucosal level.

Animals↗
PubMedDate not supplied

Ureteral obstruction following allogeneic bone marrow transplantation in children.

Two patients with Ph + CML underwent URD-BMT after conditioning with Bu-Cy-LPAM. They developed hemorrhagic cystitis with an extremely complicated and painful course, caused by ureteral obstruction, requiring prolonged hospitalization. No virus other than cytomegalovirus was found and in both cases was attributed to Cy use. Treatment is usually conservative, but in the case of severe obstruction, a surgical approach should be considered and performed as early as possible to preserve renal function.

Adolescent↗
PubMedDate not supplied

Mechanism of acute toxicity of IL-1 beta in mice.

Human recombinant IL-1 beta was able to kill C3H/HeJ mice only when inoculated intravenously at very high doses. IL-1 beta, inoculated at 100 mg/kg i.v. as a bolus, induced a shock-like state characterized by anorexia, severe hypothermia and hypoglycemia and persistent neutrophilia, leading to death in 55% of animals generally between 24 and 48 h. In contrast, the noninflammatory adjuvant IL-1 beta peptide VQGEESNDK (position 163-171) did not induce any toxic effect in vivo, when administered following the same schedule. At variance with what was previously observed in endotoxin induced shock, IL-1 beta induced death was not preceded by appearance of circulating TNF. On the other hand, very high and persistent levels of circulating IL-6 could be detected after lethal IL-1 beta administration. Treatment of mice with ibuprofen or with chlorpromazine, both known to counteract some of the toxic effects of IL-1 in vivo, could protect from IL-1 beta induced mortality. Both drugs, at doses protecting from IL-1 beta induced death, were able to abolish IL-1 beta-induced rise of circulating phospholipase A2 (PLA2) activity, and the subsequent generation of toxic PLA2-derived metabolites.

Amino Acid Sequence↗
PubMedDate not supplied

Defining the structural requirements of a biologically active domain of human IL-1 beta.

The immunostimulatory activity in vivo of the pleiotropic cytokine IL-1 beta can be retained by its nonapeptide VQGEESNDK, in position 163-171. A series of shorter and longer peptides around this position has been assayed for IL-1-like biological activity, in order to identify the structural requirements for full expression of adjuvant capacity. Elongated peptides, comprising the loop region 165-169 and up to six amino acids in the preceding beta strand or up to seven amino acids in the following beta strand, showed activity comparable or lower than that of the nonapeptide 163-171. This would indicate that the beta strand sequences are not required for optimizing the active conformation of the immunostimulatory IL-1 beta moiety. Accordingly, stabilization of the 163-171 peptide conformation by cyclization did not increase its biological activity. In contrast, the pentapeptide GEESN, corresponding the exposed loop 165-169 between two beta strands, had biological activity higher than that of the 163-171 nonapeptide and fully comparable to that of the entire IL-1 beta protein. Thus, the highly exposed fragment 165-169 within the IL-1 beta molecule may be the structure selectively responsible for the IL-1 beta immunostimulatory capacity in vivo.

Adjuvants, Immunologic↗
PubMedDate not supplied

Peyer's patch lymphocytes express natural cytotoxicity but not natural killer activity.

The distribution of natural cytotoxic (NC) cells in the gut-associated lymphoid tissues (GALT) and in peripheric lymphoid organs was analyzed in comparison to that of natural killer (NK) cells. It was found that cells from the intestinal epithelium, mesenteric lymph nodes and spleen possess significant levels of NC and NK activity, whereas in thymus and popliteal lymph nodes both the natural activities are negligible. As previously shown for splenocytes, the NC activity of GALT cells is detectable in the 16-hour assays and not in the 4-hour assays. Interestingly, Peyer patches lymphocytes (PPL) possess extremely high NC activity but no NK activity. The NC activity of PPL is still high in NK-deficient mouse strains such as A/J and SJL/J. To further support the observation that the effector PPL are truly NC cells, it was shown that, as previously reported for spleen NC activity, overnight incubation at 37 degrees C of the lymphocytes only marginally affected the cytotoxicity of PPL, which could in turn be augmented by interleukin-3 (IL-3) containing supernatants. On the contrary, IL-2 could not increase NC or NK activity by PPL whilst augmenting NK activity of splenocytes. Thus, for the first time a cell population is identified which expresses only NC activity and not NK and which can be positively regulated only by IL-3.

Animals↗