scholarly journals A non-bactericidal cathelicidin provides prophylactic efficacy against bacterial infection by driving phagocyte influx

2021 ◽  
Author(s):  
Yang Yang ◽  
Jing Wu ◽  
Qiao Li ◽  
Lixian Mu ◽  
Li Hui ◽  
...  
Keyword(s):  
Bacterial Infection ◽  
B Lymphocytes ◽  
Intraperitoneal Injection ◽  
Bacterial Load ◽  
Immune Defense ◽  
T And B Lymphocytes ◽  
Tree Frog ◽  
Bacterial Inoculation ◽  
Prophylactic Efficacy

AbstractThe roles of bactericidal cathelicidins against bacterial infection have been extensively studied. However, the anti-bacterial property and mechanism of action of non-bactericidal cathelicidins are rarely known. Herein, a novel naturally occurring cathelicidin (PopuCATH) from tree frog (Polypedates puerensis) didn’t show any direct anti-bacterial activity in vitro. Intriguingly, intraperitoneal injection of PopuCATH before bacterial inoculation significantly reduced the bacterial load in tree frogs and mice, and reduced the inflammatory response induced by bacterial inoculation in mice. PopuCATH pretreatment also increased the survival rates of septic mice induced by a lethal dose of bacterial inoculation or cecal ligation and puncture (CLP). Intraperitoneal injection of PopuCATH significantly drove the leukocyte influx in both frogs and mice. In mice, PopuCATH rapidly drove neutrophil, monocyte/macrophage influx in mouse abdominal cavity and peripheral blood with a negligible impact on T and B lymphocytes, and neutrophils, monocytes/macrophages, but not T and B lymphocytes, were required for the preventive efficacy of PopuCATH. PopuCATH did not directly act as chemoattractant for phagocytes, but PopuCATH obviously drove phagocyte migration when it was cultured with macrophages. PopuCATH significantly elicited chemokine/cytokine production in macrophages through activating p38/ERK mitogen-activated protein kinases (MAPKs) and NF-κB p65. PopuCATH markedly enhanced neutrophil phagocytosis via promoting the release of neutrophil extracellular traps (NETs). Additionally, PopuCATH showed low side effects both in vitro and in vivo. Collectively, PopuCATH acts as a host-based immune defense regulator that provides prophylactic efficacy against bacterial infection without direct antimicrobial effects. Our findings reveal a non-bactericidal cathelicidin which possesses unique anti-bacterial action, and highlight the potential of PopuCATH to prevent bacterial infection.

scholarly journals CELL INTERACTIONS IN THE IMMUNE RESPONSE IN VITRO

1972 ◽  
Vol 136 (4) ◽  
pp. 737-760 ◽  
Author(s):  
Marc Feldmann
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
B Lymphocytes ◽  
Cell Interaction ◽  
T And B Lymphocytes ◽  
Activated T Cells ◽  
Cell Cooperation

The mechanism of interaction of T and B lymphocytes was investigated in an in vitro hapten carrier system using culture chambers with two compartments separated by a cell impermeable nucleopore membrane. Because specific cell interaction occurred efficiently across this membrane, contact of T and B lymphocytes was not essential for cooperation which must have been mediated by a subcellular component or "factor." By using different lymphoid cell populations in the lower culture chamber and activated thymus cells in the upper chamber (with antigen present in both), it was found that the antigen-specific mediator acted indirectly on B cells, through the agency of macrophages. Macrophages which had been cultured in the presence of activated T cells and antigen acquired the capacity to specifically induce antibody responses in B cell-containing lymphoid populations. Trypsinization of these macrophages inhibited their capacity to induce immune responses, indicating that the mediator of cell cooperation is membrane bound. By using antisera to both the haptenic and carrier determinants of the antigen as blocking reagents, it was demonstrated that the whole antigen molecule was present on the surface of macrophages which had been exposed to activated T cells and antigen. Because specifically activated T cells were essential a component of the antigen-specific mediator must be derived from these cells. By using anti-immunoglobulin sera as inhibitors of the binding of the mediator to macrophages, the T cell component was indeed found to contain both κ- and µ-chains and was thus presumably a T cell-derived immunoglobulin. It was proposed that cell cooperation is mediated by complexes of T cell IgM and antigen, bound to the surface of macrophage-like cells, forming a lattice of appropriately spaced antigenic determinants. B cells become immunized by interacting with this surface. With this mechanism of cell cooperation, the actual pattern of antigen-B cell receptor interactions in immunization would be the same with both thymus-dependent and independent antigens. An essential feature of the proposed mechanism of cell cooperation is that macrophage-B cell interaction must occur at an early stage of the antibody response, a concept which is supported by many lines of evidence. Furthermore this mechanism of cell interaction can be elaborated to explain certain phenomena such as the highly immunogenic macrophage-bound antigen, antigenic competition, the distinction between immunity and tolerance in B lymphocytes, and the possible mediation of tolerance by T lymphocytes.

scholarly journals Expression of c-myb and B-myb, but not A-myb, correlates with proliferation in human hematopoietic cells

Blood ◽  
1991 ◽  
Vol 77 (1) ◽  
pp. 149-158 ◽  
Author(s):  
J Golay ◽  
A Capucci ◽  
M Arsura ◽  
M Castellano ◽  
V Rizzo ◽  
...  
Keyword(s):  
B Cells ◽  
B Lymphocytes ◽  
Cellular Proliferation ◽  
Cell Types ◽  
T And B Lymphocytes ◽  
Thymidine Uptake ◽  
Mitogenic Stimulation ◽  
Myb Gene ◽  
Normal Human

Abstract The steady-state expression of three members of the myb family of genes, c-myb, B-myb, and A-myb, was studied in four purified normal human hematopoietic cell types, ie, T and B lymphocytes, monocytes, and granulocytes. The c-myb proto-oncogene is low to undetectable in resting T and B lymphocytes and shows a biphasic induction in both cell types after mitogenic stimulation, with a first peak at 3 hours and a second and stronger induction at 44 to 72 hours. Study of the B-myb gene showed that this gene is low to undetectable in resting T or B cells and is strongly induced after mitogenic stimulation with a peak between 44 and 72 hours in both cell types. Finally, the A-myb gene shows a pattern of expression in lymphocytes different from that of c- myb and B-myb. It is expressed in resting T lymphocytes and its levels gradually decrease after mitogenic stimulation to become undetectable at 48 hours. It is also expressed in a subpopulation of large B lymphocytes but not in in vitro activated B cells. Neither of the three members of the myb family of genes was expressed in monocytes and granulocytes, even after functional activation of these cells. Taken together, these data bring further evidence for the role of c-myb in cellular proliferation and on the basis of the kinetics of its induction relative to thymidine uptake, we hypothesize that it may have a role during G1 progression in addition to that already documented for entry into S phase. Furthermore, our studies indicate that another member of the myb family of genes, B-myb, may also be involved in cellular proliferation, because its expression correlates with the induction of mitogenesis.

Use of an autologous reaction in vitro to assess contributions of T and B lymphocytes to immune hyperreactivity of atopics

1989 ◽  
Vol 19 (2) ◽  
pp. 163-168 ◽  
Author(s):  
J. S. DUKE-COHAN ◽  
RALY HIRT ◽  
M. ROTTEM ◽  
A. BEN-ZVI ◽  
A. RUBINOW ◽  
...  
Keyword(s):  
B Lymphocytes ◽  
T And B Lymphocytes

scholarly journals CELL INTERACTIONS BETWEEN HISTOINCOMPATIBLE T AND B LYMPHOCYTES

1973 ◽  
Vol 137 (6) ◽  
pp. 1405-1418 ◽  
Author(s):  
David H. Katz ◽  
Toshiyuki Hamaoka ◽  
Baruj Benacerraf
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
B Lymphocytes ◽  
B Lymphocyte ◽  
Cell Interaction ◽  
Antibody Responses ◽  
T And B Lymphocytes ◽  
Cooperative Interactions

Several experimental approaches, designed specifically to circumvent the possible contribution of a complicating "allogeneic effect," have been successfully used to answer the question of physiologic cooperative interactions between histoincompatible T and B lymphocytes in antibody responses to hapten-protein conjugates. This was accomplished for in vivo cell transfer studies by using an F1 hybrid host as the recipient of irradiated, carrier-primed T lymphocytes from one parent and 2,4-dinitrophenyl (DNP)-primed B lymphocytes from the opposite strain. Under these conditions, very good T-B cell cooperative interactions were observed to occur between T and B lymphocyte populations derived from syngeneic donors, whereas no cooperative response was obtained when T cells were derived from one parental strain and B cells from the other. Corroborative experiments were performed in a totally in vitro system in which DNP-primed B cells developed good secondary anti-DNP antibody responses in vitro to soluble DNP-keyhole limpet hemocyanin (KLH) when cultured in the presence of irradiated KLH-primed T cells derived from syngenic donors but not from allogeneic donors. The failure of histoincompatible T and B lymphocytes to effect physiologic cooperative interactions has important implications for our understanding of how such interactions normally occur. The possibility that these results reflect the existence of a "block" of some sort to cell-cell interaction by virtue of the presence of a foreign major histocompatibility antigen on the surface of either cell has been definitively ruled out in the present studies. These observations demonstrate that the gene(s) that conditions the capability for physiologic T-B cell cooperation must be shared in common by the respective cell types, and suggest, furthermore, that this gene (or genes) belongs to the major histocompatibility system of the mouse. These findings, together with other relevant phenomena described previously, have led us to postulate that there exists on the B lymphocyte surface an "acceptor" molecule either for the putative active T cell product or for the T cell itself. The important genetic considerations and the possible sequence of events surrounding the actual T-B cell interaction implied by these postulates are discussed in detail.

Cytotoxicity and accumulation of Hg, Ag, Cd, Cu, Pb and Zn in human peripheral T and B lymphocytes and monocytes In Vitro

1994 ◽  
Vol 25 (8) ◽  
pp. 1621-1633 ◽  
Author(s):  
I-L. Steffensen ◽  
O.J. Mesna ◽  
E. Andruchow ◽  
E. Namork ◽  
K. Hylland ◽  
...  
Keyword(s):  
B Lymphocytes ◽  
T And B Lymphocytes
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