scholarly journals CD4+ T Lymphocytes from Anaplasma marginale Major Surface Protein 2 (MSP2) Vaccinees Recognize Naturally Processed Epitopes Conserved in MSP3

2004 ◽  
Vol 72 (6) ◽  
pp. 3688-3692 ◽  
Author(s):  
Wendy C. Brown ◽  
Guy H. Palmer ◽  
Kelly A. Brayton ◽  
Patrick F. M. Meeus ◽  
Anthony F. Barbet ◽  
...  
Keyword(s):  
T Lymphocytes ◽  
T Lymphocyte ◽  
Antigenic Variation ◽  
Surface Protein ◽  
Anaplasma Marginale ◽  
Lymphocyte Response ◽  
Major Surface Protein ◽  
C Terminus ◽  
N Terminus ◽  
Major Surface

ABSTRACT Major surface protein 2 (MSP2) and MSP3 of the persistent bovine ehrlichial pathogen Anaplasma marginale are immunodominant proteins that undergo antigenic variation. The recently completed sequence of MSP3 revealed blocks of amino acids in the N and C termini that are conserved with MSP2. This study tested the hypothesis that CD4+ T cells specific for MSP2 recognize naturally processed epitopes conserved in MSP3. At least one epitope in the N terminus and two in the C terminus of MSP2 were also processed from MSP3 and presented to CD4+ T lymphocytes from MSP2-immunized cattle. This T-lymphocyte response to conserved and partially conserved epitopes may contribute to the immunodominance of MSP2 and MSP3.

scholarly journals CD4+ T Lymphocytes from Calves Immunized withAnaplasma marginale Major Surface Protein 1 (MSP1), a Heteromeric Complex of MSP1a and MSP1b, Preferentially Recognize the MSP1a Carboxyl Terminus That Is Conserved among Strains

2001 ◽  
Vol 69 (11) ◽  
pp. 6853-6862 ◽  
Author(s):  
Wendy C. Brown ◽  
Guy H. Palmer ◽  
Harris A. Lewin ◽  
Travis C. McGuire
Keyword(s):  
T Lymphocytes ◽  
T Lymphocyte ◽  
Protective Immunity ◽  
B Lymphocyte ◽  
Surface Protein ◽  
Specific Response ◽  
Major Surface Protein ◽  
Ifn Γ ◽  
Major Surface ◽  
Lymphocyte Responses

ABSTRACT Native major surface protein 1 (MSP1) of the ehrlichial pathogenAnaplasma marginale induces protective immunity in calves challenged with homologous and heterologous strains. MSP1 is a heteromeric complex of a single MSP1a protein covalently associated with MSP1b polypeptides, of which at least two (designated MSP1F1 and MSP1F3) in the Florida strain are expressed. Immunization with recombinant MSP1a and MSP1b alone or in combination fails to provide protection. The protective immunity in calves immunized with native MSP1 is associated with the development of opsonizing and neutralizing antibodies, but CD4+ T-lymphocyte responses have not been evaluated. CD4+ T lymphocytes participate in protective immunity to ehrlichial pathogens through production of gamma interferon (IFN-γ), which promotes switching to high-affinity immunoglobulin G (IgG) and activation of phagocytic cells to produce nitric oxide. Thus, an effective vaccine for A. marginaleand related organisms should contain both T- and B-lymphocyte epitopes that induce a strong memory response that can be recalled upon challenge with homologous and heterologous strains. This study was designed to determine the relative contributions of MSP1a and MSP1b proteins, which contain both variant and conserved amino acid sequences, in stimulating memory CD4+ T-lymphocyte responses in calves immunized with native MSP1. Peripheral blood mononuclear cells and CD4+ T-cell lines from MSP1-immunized calves proliferated vigorously in response to the immunizing strain (Florida) and heterologous strains of A. marginale. The conserved MSP1-specific response was preferentially directed to the carboxyl-terminal region of MSP1a, which stimulated high levels of IFN-γ production by CD4+ T cells. In contrast, there was either weak or no recognition of MSP1b proteins. Paradoxically, all calves developed high titers of IgG antibodies to both MSP1a and MSP1b polypeptides. These findings suggest that in calves immunized with MSP1 heteromeric complex, MSP1a-specific T lymphocytes may provide help to MSP1b-specific B lymphocytes. The data provide a basis for determining whether selected MSP1a CD4+ T-lymphocyte epitopes and selected MSP1a and MSP1b B-lymphocyte epitopes presented on the same molecule can stimulate a protective immune response.

scholarly journals Selection for Simple Major Surface Protein 2 Variants during Anaplasma marginale Transmission to Immunologically Naïve Animals

2006 ◽  
Vol 75 (3) ◽  
pp. 1502-1506 ◽  
Author(s):  
Guy H. Palmer ◽  
James E. Futse ◽  
Christina K. Leverich ◽  
Donald P. Knowles ◽  
Fred R. Rurangirwa ◽  
...  
Keyword(s):  
Adaptive Immunity ◽  
Antigenic Variation ◽  
Surface Protein ◽  
Anaplasma Marginale ◽  
Selective Advantage ◽  
Immune Selection ◽  
Animal Host ◽  
Major Surface Protein ◽  
Selection For ◽  
Major Surface

ABSTRACT Anaplasma marginale, a rickettsial pathogen, evades clearance in the animal host by antigenic variation. Under immune selection, A. marginale expresses complex major surface protein 2 mosaics, derived from multiple donor sequences. However, these mosaics have a selective advantage only in the presence of adaptive immunity and are rapidly replaced by simple variants following transmission.

scholarly journals The Repertoire of Anaplasma marginale Antigens Recognized by CD4+ T-Lymphocyte Clones from Protectively Immunized Cattle Is Diverse and Includes Major Surface Protein 2 (MSP-2) and MSP-3

1998 ◽  
Vol 66 (11) ◽  
pp. 5414-5422 ◽  
Author(s):  
Wendy C. Brown ◽  
Daming Zhu ◽  
Varda Shkap ◽  
Travis C. McGuire ◽  
Edmour F. Blouin ◽  
...  
Keyword(s):  
T Lymphocyte ◽  
Surface Protein ◽  
Anaplasma Marginale ◽  
Surface Proteins ◽  
Interleukin 4 ◽  
Protein Vaccine ◽  
Major Surface Protein ◽  
Th Cell ◽  
Cell Clones ◽  
Major Surface

ABSTRACT Major surface proteins of Anaplasma marginale are vaccine candidates. We recently demonstrated that immunization of calves with outer membranes of the Florida strain ofA. marginale resulted in protective immunity that correlated with a memory CD4+ T-lymphocyte response specific for major surface protein 1 (MSP-1), MSP-2, and MSP-3 (W. C. Brown, V. Shkap, D. Zhu, T. C. McGuire, W. Tuo, T. F. McElwain, and G. H. Palmer, Infect. Immun. 66:5406–5413, 1998). As immunogens, these proteins have been shown to induce complete or partial protection against homologous challenge. To further define the T helper (Th) cell response to these and other A. marginale antigens and to determine conservation of Th cell epitopes among genetically distinct A. marginalestrains, Th cell clones obtained prior to challenge from three immunized calves were characterized for antigen-specific responses. Nine distinct antigenic profiles were defined by 11 Th cell clones derived by stimulation with the Florida strain. Several clones responded to MSP-2, MSP-3, or both. All of these MSP-2- or MSP-3-specific clones and the majority of other clones that did not respond to MSPs recognized all bovine blood-passaged strains ofA. marginale. These results demonstrate conservation of certain Th cell epitopes between MSP-2 and MSP-3 and show that Th cell epitopes in MSP-2, MSP-3, and undefined antigens are conserved among strains of A. marginale. Of seven clones that responded to the blood-passaged Virginia strain, two did not recognize antigen prepared from this strain cultured in tick cells, suggesting differences in the antigenic composition between these stages. Analysis of the cytokines expressed by the Th cells revealed that all clones expressed gamma interferon and tumor necrosis factor alpha, and most coexpressed interleukin-4. Our results provide a rationale for identifying Th cell epitopes conserved among different strains of A. marginale for inclusion in a nucleic acid or recombinant protein vaccine.

scholarly journals Expression of Anaplasma marginale Major Surface Protein 2 Variants in Persistently Infected Ticks

2001 ◽  
Vol 69 (8) ◽  
pp. 5151-5156 ◽  
Author(s):  
José de la Fuente ◽  
Katherine M. Kocan
Keyword(s):  
Immune Response ◽  
Salivary Glands ◽  
Antigenic Variation ◽  
Surface Protein ◽  
Anaplasma Marginale ◽  
Dermacentor Variabilis ◽  
Persistently Infected ◽  
Major Surface Protein ◽  
Persistent Infections ◽  
Major Surface

ABSTRACT Anaplasma marginale, an intraerythrocytic ehrlichial pathogen of cattle, establishes persistent infections in both vertebrate (cattle) and invertebrate (tick) hosts. The ability ofA. marginale to persist in cattle has been shown to be due, in part, to major surface protein 2 (MSP2) variants which are hypothesized to emerge in response to the bovine immune response. MSP2 antigenic variation has not been studied in persistently infected ticks. In this study we analyzed MSP2 in A. marginalepopulations from the salivary glands of male Dermacentor variabilis persistently infected with A. marginaleafter feeding successively on one susceptible bovine and three sheep. New MSP2 variants appeared in each A. marginale population, and sequence alignment of the MSP2 variants revealed multiple amino acid substitutions, insertions, and deletions. These results suggest that selection pressure on MSP2 occurred in tick salivary glands independent of the bovine immune response.

scholarly journals Anaplasma marginale Major Surface Protein 2 CD4+-T-Cell Epitopes Are Evenly Distributed in Conserved and Hypervariable Regions (HVR), Whereas Linear B-Cell Epitopes Are Predominantly Located in the HVR

2004 ◽  
Vol 72 (12) ◽  
pp. 7360-7366 ◽  
Author(s):  
Jeffrey R. Abbott ◽  
Guy H. Palmer ◽  
Chris J. Howard ◽  
Jayne C. Hope ◽  
Wendy C. Brown
Keyword(s):  
T Cell ◽  
B Cell ◽  
Surface Protein ◽  
Anaplasma Marginale ◽  
T Cell Epitopes ◽  
B Cell Epitopes ◽  
Major Surface Protein ◽  
Hypervariable Regions ◽  
Major Surface ◽  
Linear B

ABSTRACT Organisms in the genus Anaplasma express an immunodominant major surface protein 2 (MSP2), composed of a central hypervariable region (HVR) flanked by highly conserved regions. Throughout Anaplasma marginale infection, recombination results in the sequential appearance of novel MSP2 variants and subsequent control of rickettsemia by the immune response, leading to persistent infection. To determine whether immune evasion and selection for variant organisms is associated with a predominant response against HVR epitopes, T-cell and linear B-cell epitopes were localized by measuring peripheral blood gamma interferon-secreting cells, proliferation, and antibody binding to 27 overlapping peptides spanning MSP2 in 16 cattle. Similar numbers of MSP2-specific CD4+ T-cell epitopes eliciting responses of similar magnitude were found in conserved and hypervariable regions. T-cell epitope clusters recognized by the majority of animals were identified in the HVR (amino acids [aa] 171 to 229) and conserved regions (aa 101 to 170 and 272 to 361). In contrast, linear B-cell epitopes were concentrated in the HVR, residing within hydrophilic sequences. The pattern of recognition of epitope clusters by T cells and of HVR epitopes by B cells is consistent with the influence of protein structure on epitope recognition.

scholarly journals Antigenic Variation of Anaplasma Marginale: Major Surface Protein 2 Diversity during Cyclic Transmission between Ticks and Cattle

2001 ◽  
Vol 69 (5) ◽  
pp. 3057-3066 ◽  
Author(s):  
A. F. Barbet ◽  
Jooyoung Yi ◽  
Anna Lundgren ◽  
B. R. McEwen ◽  
E. F. Blouin ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Salivary Glands ◽  
Antigenic Variation ◽  
Hypervariable Region ◽  
Surface Protein ◽  
Genomic Expression ◽  
Major Surface Protein ◽  
Expression Site ◽  
Major Surface ◽  
Tick Salivary Glands

ABSTRACT The rickettsial pathogen Anaplasma marginale expresses a variable immunodominant outer membrane protein, major surface protein 2 (MSP2), involved in antigenic variation and long-term persistence of the organism in carrier animals. MSP2 contains a central hypervariable region of about 100 amino acids that encodes immunogenic B-cell epitopes that induce variant-specific antibodies during infection. Previously, we have shown that MSP2 is encoded on a polycistronic mRNA transcript in erythrocyte stages of A. marginale and defined the structure of the genomic expression site for this transcript. In this study, we show that the same expression site is utilized in stages of A. marginale infecting tick salivary glands. We also analyzed the variability of this genomic expression site in Oklahoma strain A. marginale transmitted from in vitro cultures to cattle and between cattle and ticks. The structure of the expression site and flanking regions was conserved except for sequence that encoded the MSP2 hypervariable region. At least three different MSP2 variants were encoded in each A. marginalepopulation. The major sequence variants did not change on passage ofA. marginale between culture, acute erythrocyte stage infections, and tick salivary glands but did change during persistent infections of cattle. The variant types found in tick salivary glands most closely resembled those present in bovine blood at the time of acquisition of infection, whether infection was acquired from an acute or from a persistent rickettsemia. These variations in structure of an expression site for a major, immunoprotective outer membrane protein have important implications for vaccine development and for obtaining an improved understanding of the mechanisms of persistence of ehrlichial infections in humans, domestic animals, and reservoir hosts.

scholarly journals Comparison between indirect enzyme-linked immunosorbent assays for Anaplasma marginale antibodies with recombinant major surface protein 5 and initial body antigens

2006 ◽  
Vol 101 (5) ◽  
pp. 511-516 ◽  
Author(s):  
Virgínia MG Silva ◽  
Flábio R Araújo ◽  
Claudio R Madruga ◽  
Cleber O Soares ◽  
Raul H Kessler ◽  
...  
Keyword(s):  
Surface Protein ◽  
Anaplasma Marginale ◽  
Major Surface Protein ◽  
Immunosorbent Assays ◽  
Major Surface

Phylogeography of New World isolates of Anaplasma marginale based on major surface protein sequences

2002 ◽  
Vol 88 (3) ◽  
pp. 275-285 ◽  
Author(s):  
José de la Fuente ◽  
Ronald A Van Den Bussche ◽  
Jose C Garcia-Garcia ◽  
Sergio D Rodrı́guez ◽  
Miguel A Garcı́a ◽  
...  
Keyword(s):  
New World ◽  
Protein Sequences ◽  
Surface Protein ◽  
Anaplasma Marginale ◽  
Major Surface Protein ◽  
Major Surface
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