scholarly journals Ehrlichia chaffeensis Infections in Drosophila melanogaster

2009 ◽  
Vol 77 (11) ◽  
pp. 4815-4826 ◽  
Author(s):  
Alison Luce-Fedrow ◽  
Tonia Von Ohlen ◽  
Stephen K. Chapes
Keyword(s):  
Drosophila Melanogaster ◽  
Amblyomma Americanum ◽  
Immune Defense ◽  
Ehrlichia Chaffeensis ◽  
Humoral Immune ◽  
Humoral Immune Responses ◽  
Defense Induction ◽  
Humoral Responses ◽  
Human Monocytic Ehrlichiosis

ABSTRACT Ehrlichia chaffeensis is an obligate, intracellular bacterium, transmitted by the tick Amblyomma americanum, and is the causative agent of human monocytic ehrlichiosis infections. We previously demonstrated that E. chaffeensis is capable of growing in Drosophila S2 cells. Therefore, we tested the hypothesis that E. chaffeensis can infect adult Drosophila melanogaster. Adult Drosophila organisms were experimentally challenged with intra-abdominal injections of bacteria. Ehrlichia-infected flies showed decreased survival compared to wild-type flies, and bacteria isolated from flies could reinfect mammalian macrophages. Ehrlichia infections activated both the cellular and humoral immune responses in the fly. Hemocytes phagocytosed bacteria after injection, and antimicrobial peptide pathways were induced following infection. Increased pathogenicity in flies carrying mutations in genes in both the Toll and Imd pathways suggests that both immune defense pathways participate in host defense. Induction of Drosophila cellular and humoral responses and the in vivo replication of E. chaffeensis suggests that D. melanogaster is a suitable host for E. chaffeensis. In the future, it will be a useful tool to unlock some of the in vivo mysteries of this arthropod-borne bacterium.

scholarly journals In vivo CD40-gp39 interactions are essential for thymus-dependent humoral immunity. II. Prolonged suppression of the humoral immune response by an antibody to the ligand for CD40, gp39.

1993 ◽  
Vol 178 (5) ◽  
pp. 1567-1575 ◽  
Author(s):  
T M Foy ◽  
D M Shepherd ◽  
F H Durie ◽  
A Aruffo ◽  
J A Ledbetter ◽  
...  
Keyword(s):  
Humoral Immunity ◽  
Cell Activation ◽  
Keyhole Limpet Hemocyanin ◽  
B Cell Activation ◽  
Protein Antigens ◽  
Humoral Immune ◽  
Humoral Immune Responses ◽  
Humoral Responses

The ligand for CD40 has been recently identified as a 39-kd protein, gp39, expressed on the surface of activated CD4+ T helper cells (Th). In vitro, soluble CD40 and anti-gp39 have been shown to block the ability of Th to activate B cells, suggesting that gp39-CD40 interactions are important to T cell-dependent B cell activation. Here it is shown that in vivo administration of anti-gp39 dramatically reduced both primary and secondary humoral immune responses to erythrocytes and soluble protein antigens without altering responses to the T-independent type II antigen, trinitrophenyl-Ficoll. Treatment of mice for 4 d with anti-gp39 inhibited the anti-sheep red blood cell (SRBC) response for at least 3 wk and inhibited the expression of all immunoglobulin isotypes in secondary responses to the protein antigen, keyhole limpet hemocyanin. To examine the direct effect of anti-gp39 on Th function, SRBC-immune Th cells from anti-gp39-treated mice were adoptively transferred and shown to be fully capable of providing help. These results suggest that anti-gp39 treatment does not cause Th deletion or anergy. Anti-gp39 may mediate its profound immunosuppressive effects on humoral immunity by blocking gp39-CD40 interactions. Moreover, these studies establish gp39-CD40 as an important receptor-ligand pair for the targeting of therapeutic antibodies to control thymus-dependent humoral responses.

scholarly journals Purified Hexameric Epstein-Barr Virus-Encoded BARF1 Protein for Measuring Anti-BARF1 Antibody Responses in Nasopharyngeal Carcinoma Patients

2010 ◽  
Vol 18 (2) ◽  
pp. 298-304 ◽  
Author(s):  
E. K. Hoebe ◽  
S. H. Hutajulu ◽  
J. van Beek ◽  
S. J. Stevens ◽  
D. K. Paramita ◽  
...  
Keyword(s):  
Nasopharyngeal Carcinoma ◽  
Epstein Barr Virus ◽  
Antibody Responses ◽  
Enzyme Linked Immunosorbent Assay ◽  
Humoral Immune ◽  
Barr Virus ◽  
Humoral Immune Responses ◽  
Human Sera ◽  
Epstein Barr ◽  
Humoral Responses

ABSTRACTWHO type III nasopharyngeal carcinoma (NPC) is highly prevalent in Indonesia and 100% associated with Epstein-Barr virus (EBV). NPC tumor cells express viral proteins, including BARF1, which is secreted and is considered to have oncogenic and immune-modulating properties. Recently, we found conserved mutations in the BARF1 gene in NPC isolates. This study describes the expression and purification of NPC-derived BARF1 and analyzes humoral immune responses against prototype BARF1 (B95-8) and purified native hexameric BARF1 in sera of Indonesian NPC patients (n= 155) compared to healthy EBV-positive (n= 56) and EBV-negative (n= 16) individuals. BARF1 (B95-8) expressed inEscherichia coliand baculovirus, as well as BARF1-derived peptides, did not react with IgG or IgA antibodies in NPC. Purified native hexameric BARF1 protein isolated from culture medium was used in enzyme-linked immunosorbent assay (ELISA) and revealed relatively weak IgG and IgA responses in human sera, although it had strong antibody responses to other EBV proteins. Higher IgG reactivity was found in NPC patients (P= 0.015) than in regional Indonesian controls or EBV-negative individuals (P< 0.001). IgA responses to native BARF1 were marginal. NPC sera with the highest IgG responses to hexameric BARF1 in ELISA showed detectable reactivity with denatured BARF1 by immunoblotting. In conclusion, BARF1 has low immunogenicity for humoral responses and requires native conformation for antibody binding. The presence of antibodies against native BARF1 in the blood of NPC patients provides evidence that the protein is expressed and secreted as a hexameric protein in NPC patients.

scholarly journals MATURATION OF THE HUMORAL IMMUNE RESPONSE IN MICE

1974 ◽  
Vol 139 (2) ◽  
pp. 249-263 ◽  
Author(s):  
Patricia G. Spear ◽  
Gerald M. Edelman
Keyword(s):  
T Cell ◽  
B Cells ◽  
Cell Function ◽  
Spleen Cells ◽  
Con A ◽  
Humoral Immune ◽  
Humoral Immune Responses ◽  
Humoral Antibodies

In spite of the prenatal appearance of immunoglobulin-bearing lymphocytes and θ-positive lymphocytes in the spleens of Swiss-L mice, these mice are not able to produce detectable levels of humoral antibodies in response to antigen until after 1 wk of age. Adult levels of response are not achieved until 4–8 wk of age. In the presence of bacterial lipopolysaccharides, which can substitute for or enhance T-cell function, the B cells from young Swiss-L mice were found to be indistinguishable in function from adult B cells, both with respect to the numbers of plaque-forming cells (PFC) produced in vitro in response to antigen and with respect to the kinetics of PFC induction. The spleen cells from young Swiss-L mice are significantly less sensitive than adult spleen cells, however, to stimulation by the T cell mitogens, concanavalin A (Con A) and phytohemagglutinin (PHA). Very few Con A-responsive cells could be detected at birth but the numbers increased sharply with age until 3 wk after birth. On the other hand, PHA-responsive cells could not be detected in the spleen until about 3 wk of age. The latter cells were found to respond also to Con A, but at a lower dose (1 µg/ml) than that required for the bulk of the Con A-responsive cells (3 µg/ml). The cells that respond both to PHA and to Con A appear in the spleen at about the time that Swiss-L mice acquire the ability to produce humoral antibodies, and these cells can be depleted from the spleen by the in vivo administration of antithymocyte serum. The development of humoral immune responses in these mice therefore appears to be correlated with the appearance of recirculating T lymphocytes that are responsive both to PHA and to Con A.

In vivo inhibition of cell-mediated and humoral immune responses to cellular antigens by SV-IV, a major protein secreted from the rat seminal vesicle epithelium

1995 ◽  
Vol 28 (1) ◽  
pp. 15-30 ◽  
Author(s):  
Caterina Romano-Carratelli ◽  
Marilena Galdiero ◽  
Immacolata Nuzzo ◽  
Concetta Bentivoglio ◽  
Raffaele Porta ◽  
...  
Keyword(s):  
Immune Responses ◽  
Seminal Vesicle ◽  
Major Protein ◽  
Humoral Immune ◽  
Humoral Immune Responses ◽  
Rat Seminal Vesicle

Chondroitin sulfate activates B cells in vitro, expands CD138+cells in vivo, and interferes with established humoral immune responses

2014 ◽  
Vol 96 (1) ◽  
pp. 65-72 ◽  
Author(s):  
Hilke Brühl ◽  
Josef Cihak ◽  
Nicole Goebel ◽  
Yvonne Talke ◽  
Kerstin Renner ◽  
...  
Keyword(s):  
B Cells ◽  
Immune Responses ◽  
Chondroitin Sulfate ◽  
Humoral Immune ◽  
Humoral Immune Responses

Host protective humoral immune responses to Schistosoma mansoni infections in the rat. Kinetics of hyperimmune serum-dependent sensitivity and elimination of schistosomes in a passive transfer system

Parasitology ◽  
1981 ◽  
Vol 83 (3) ◽  
pp. 559-574 ◽  
Author(s):  
Beverley L. Mangold ◽  
P. M. Knopf
Keyword(s):  
Schistosoma Mansoni ◽  
Post Infection ◽  
Passive Transfer ◽  
Transfer System ◽  
Rat Serum ◽  
Hyperimmune Serum ◽  
Humoral Immune ◽  
Humoral Immune Responses ◽  
Serum Dependent

SUMMARYA passive transfer system, dependent upon hyperimmune rat serum, was used to study in vivo protective humoral immunity to Schistosoma mansoni infection in Fischer rats. Infected recipients of hyperimmune serum exhibited a significant reduction (51%) in the number of recovered adult schistosomes relative to infected recipients of normal rat serum. Furthermore, schistosomula were equally sensitive to the effects of hyperimmune serum injected up to and including 7 days post-infection, a phenomenon which was termed ‘extended sensitivity’. Schistosomula were beginning to lose sensitivity to the effects of hyperimmune serum by the 8th day post-infection and were completely refractile by the 9th day. In addition, it was demonstrated that parasite elimination occurred after the lung stage. Some protection was also observed when hyperimmune rat serum was transferred to mice as late as 5 days post-infection.

scholarly journals The in vivo function of a noncanonical TRAF2-binding domain in the C-terminus of CD40 in driving B-cell growth and differentiation

Blood ◽  
2007 ◽  
Vol 110 (1) ◽  
pp. 193-200 ◽  
Author(s):  
Li-Fan Lu ◽  
Cory L. Ahonen ◽  
Evan F. Lind ◽  
Vanitha S. Raman ◽  
W. James Cook ◽  
...  
Keyword(s):  
Immune Responses ◽  
B Cell ◽  
Cell Activation ◽  
Affinity Maturation ◽  
Functional Domain ◽  
Antibody Isotype ◽  
Humoral Immune ◽  
Humoral Immune Responses ◽  
Cell Immunity

The recruitment of tumor necrosis factor receptor–associated factors (TRAFs) 1, 2, 3, 5, and 6 to the CD40 cytoplasmic tail upon CD40 trimerization results in downstream signaling events that ultimately lead to CD40-dependent, thymus-dependent (TD) humoral immune responses. Previously, we have shown signaling through the C-terminal tail of CD40 in the absence of canonical TRAF-binding sites is capable of signaling through an alternative TRAF2-binding site. Here, we demonstrate that B cells from mice harboring CD40 with only the C-terminal tail can activate both canonical and noncanonical NFκB signaling pathways. Moreover, while lacking germinal center formation, several hallmarks of humoral immune responses including clonal B-cell activation/expansion, antibody isotype switching, and affinity maturation remain normal. This study demonstrates a new functional domain in CD40 that controls critical aspects of B-cell immunity in an in vivo setting.

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