Differences In Antibody Responses Research Articles

Evaluation of a recombinant nucleocapsid protein‐based assay for Anti‐SARS‐CoV IgG detection

A high throughput accurate assay for anti‐SARS‐CoV IgG detection is needed for large‐scale epidemiological studies. The evaluation of a commercial recombinant nucleocapsid protein‐based microtitre plate enzyme immunoassay, ELISARS™ is described. The results on 150 sera from SARS patients and 450 sera from non‐SARS controls showed that this assay had a high level of sensitivity (96.2% for late serum samples) and specificity (97.8%). The performance and setup of this assay fulfills the requirement as a screening test for large‐scale studies. A vast majority of SARS patients developed antibodies against the nucleocapsid protein. In some patients (10/45), a high level of anti‐nucleocapsid antibody appeared very early in the course of the illness. In contrast, a minority (4 of 105 patients) never developed these antibodies. The implication of differences in antibody response to the nucleocapsid protein deserves further investigation. J. Med. Virol. 75:181–184, 2005. © 2004 Wiley‐Liss, Inc.

The Larval Specific Lymphatic Filarial ALT‐2: Induction of Protection Using Protein or DNA Vaccination

Genes from the infective stage of lymphatic filarial parasites expressed at the time of host invasion have been identified as potential vaccine candidates. By screening an L3 cDNA library with sera from uninfected longstanding residents of an area endemic for onchocerciasis, so-called "endemic normals" (EN), we have cloned and characterized one such gene termed the abundant larval transcript two (ALT-2). The stage specificity of ALT-2 gene transcription and protein synthesis was confirmed by PCR using genespecific primers, and by western blot analysis of protein extracts from various stages of the parasite life cycle using specific antisera. Significant differences in antibody response to the recombinant ALT-2 were observed in endemic populations with differing clinical manifestations of lymphatic filariasis with an antibody response present in sera from 18 of 25 (72%) EN subjects compared to 9 of 25 (36%) with subclinical microfilaracmia (MF) and 14 of 25 (52%) of those with chronic lymphatic obstruction (CP) (P=0.01 for comparison of EN to CP or to MF). This differential responsiveness suggests that the protective immunity postulated to account for their uninfected status might be associated with a response to this protein. When the utility of ALT-2 as a vaccine candidate was tested in a murine model using either recombinant protein or a DNA vaccine construct, statistically significant protection was observed when compared to a control filarial gene product expressed across all stages of the parasite lifecycle (SXP-1; P=0.02 for protein and P=0.01 for the DNA vaccine) or compared to adjuvant alone. This level of protection indicates that this vaccine is a promising candidate for further development.

Antibody Response to Influenza Vaccination in Healthy Adults

The aim of this study was to assess antibody response in 184 healthy adults vaccinated with split influenza vaccine (Begrivac, Chiron Behring). Response to hemagglutinin and neuraminidase was assessed before vaccination and after 1 month by hemagglutination inhibition test and neuraminidase inhibition test. After vaccination, statistically significant increases of antibody titers, both for hemagglutinins and for neuraminidases, were observed. The post-vaccination proportion of persons with protective antihemagglutinin antibody titers ranged from 78.4%to 90.8%, while the proportion of persons with at least a fourfold increase of antihemagglutinin antibody titers ranged from 50.5% to 71.2%. All requirements of the Committee for Proprietary Medicinal Products regarding humoral response to inactivated influenza vaccine in healthy adults were fulfilled. Due to a wide range of age of the persons included in this study, the results were also analyzed in two age groups: from 20 to 45 years and from 46 to 56 years. Nevertheless, there were no statistically significant differences in antibody response between these two groups either for hemagglutinin or for neuraminidase.

Dose response of CRM 197 and tetanus toxoid-conjugated Haemophilus influenzae type b vaccines

High vaccine cost has limited use of conjugate vaccines in the developing world where the disease burden is greatest. Fixed fractional doses of Haemophilus influenzae type b (Hib) vaccines have been shown to be immunogenic, but dose responses of these vaccines in humans are needed to determine the lowest immunogenic dose as an option for lowering vaccine cost. We randomized children to receive one of five doses (0.625, 1.25, 2.5, 5.0 and 10 μg) of either a diphtheria CRM 197 or tetanus toxoid-conjugated Hib vaccine. The children received a primary three-dose series at 6, 10, and 14 weeks of age and a booster dose at 9 months. Anti-PRP IgG antibodies were measured at each vaccination, at 18 weeks, and at one week following the booster dose. Concentrations of ≥1.25 μg of HibCRM 197 vaccine produced mean anti-PRP responses at 18 weeks of ≥5.72 μg/ml and ≥0.15 μg/ml was achieved in >98% of the children with at least 79% reaching anti-PRP concentrations of ≥1.0 μg/ml. Concentrations of ≥1.25 μg of Hib-tetanus vaccine produced mean anti-PRP responses at 18 weeks of ≥8.63 μg/ml and ≥0.15 μg/ml was achieved in 100% of the children with at least 88.9% reaching anti-PRP concentrations of ≥1.0 μg/ml. While mean antibody concentrations after either vaccine decreased over time, the proportion of children with antibody levels of ≥0.15 μg/ml had not changed significantly at the 9 month measurement. Immunologic memory was demonstrated by significant increases in mean antibody concentrations one week after the booster dose for doses ≥1.25 μg of HibCRM 197 and Hib-tetanus to mean concentrations ≥37.71 and 16.07 μg/ml, respectively. There were no differences in antibody responses for vaccine doses ≥1.25 μg of the same vaccine or between the same concentrations of the two different vaccines. Our data suggest that doses of these vaccines of ≥1.25 μg may be sufficient to stimulate an immune response that offers both short and longer term protection from invasive Hib disease.

Differential antibody responses to Plasmodium falciparum-derived B-cell epitopes induced by diepitope multiple antigen peptides (MAP) containing different T-cell epitopes

Epitopes of universal character are needed when designing subunit vaccines against infectious diseases such as malaria. We have compared the immunogenicity of B-cell epitopes from the Plasmodium falciparum antigen repeats DPNANPNV (PfCS protein) and VTEEI (Pf332) when assembled with four different universal T-cell epitopes in diepitope multiple antigen peptides (MAP). T-epitopes employed were from P. falciparum antigens (CS.T3, [T *] 4 and EBP3) or from the Clostridium tetani toxin (P2). In association with either of the T-epitopes, the genetic unresponsiveness to the B-epitopes was successfully bypassed. Our results show that the immunogenicity of a T-epitope alone does not necessarily predict the ability of the T-epitope to provide T-cell help when combined with other epitopes in an immunogen. Further, the nature of the immune responses in terms of total IgG antibodies and their subclass distribution, T-cell proliferation and IFN-γ production, varied with the T-epitope and mouse strain, which may indicate the need for inclusion of a combination of different universal T-epitopes in a future malaria subunit vaccine.

Mapping of B-cell epitopes in the N-terminal repeated peptides of Anaplasma marginale major surface protein 1a and characterization of the humoral immune response of cattle immunized with recombinant and whole organism antigens.

Major surface protein (MSP) 1a of the genus type species Anaplasma marginale (Rickettsiales: Anaplasmataceae) together with MSP1b forms the MSP1 complex. MSP1a has been shown to be involved in adhesion, infection and tick transmission of A. marginale, as well as to contribute to protective immunity in cattle. A differential antibody response to MSP1a and MSP1b was observed in cattle immunized with A. marginale derived from bovine erythrocytes (anti-MSP1a response) or cultured tick cells (anti-MSP1b response). In this study, we further characterized the MSP1a antibody response of cattle using several immunogens, including recombinant MSP1a (rMSP1a) protein, erythrocyte- or tick cell culture-derived A. marginale, or a combination of tick cell culture-derived A. marginale and rMSP1a. The MSP1a antibody response to all these immunogens was directed primarily against the N-terminal region of MSP1a that contains tandemly repeated peptides, whereas low antibody levels were detected against the C-terminal portion. Linear B-cell epitopes of MSP1a were mapped using synthetic peptides representing the entire sequence of the protein that were prepared by SPOT synthesis technology. Only two peptides in the N-terminal repeats were recognized by sera from immunized cattle. These peptides shared the sequence SSAGGQQQESS, which is likely to contain the linear B-cell epitope that was recognized by the pools of bovine sera. The average differential of antibody titers against MSP1a minus those against MSP1b correlated with lower percent reductions in PCV. A preferential antibody response to MSP1a was observed in cattle immunized with erythrocyte-derived, cell culture-derived plus rMSP1a or rMSP1a alone, and the percent reduction PCV was significantly lower in these cattle as compared with the other immunization groups. These results provide insight into the bovine antibody response against A. marginale and the role of MSP1a in protection of cattle against A. marginale infection.

Relief of MMR vaccination pain using topical 4% amethocaine

Routine vaccinations are the most common source of iatrogenic pain in infants and children, however this pain is not routinely managed. 4% amethocaine gel is a new anaesthetic agent that achieves anaesthesia within 30-45 minutes of application; this shortened application time may make its use feasible in busy clinical settings. The objective of this study was to determine the efficacy and safety of 4% amethocaine for reducing the pain of measles-mumps-rubella (MMR) vaccination. A randomized, double-blind, placebo-controlled design was employed. Healthy 1 year old infants receiving their routine 12-month MMR vaccination were recruited and randomized to receive 1g of amethocaine or a visually identical placebo for 30 minutes prior to vaccination. The vaccination procedure was videotaped and the tape used later for pain assessment. The Modified Behavioural Pain Scale (MBPS) was the primary outcome measure for pain. A 5–mL sample of blood was collected from infants 1 month post-vaccination to assess antibody titers using enzyme immunoassay. The amethocaine group (n = 61) had significantly lower pain scores than the placebo group (n = 59); 1.51 vs. 2.29 (p=0.029). There was no difference in antibody response between the amethocaine and placebo treatment groups(p<0.05). Amethocaine reduced the pain of MMR vaccination without compromisng the immunogenicity of the vaccine. Clinical Pharmacology & Therapeutics (2004) 75, P75–P75; doi: 10.1016/j.clpt.2003.11.285

Antibody responses to Brugia malayi antigens induced by DNA vaccination

BackgroundDNA vaccination is a convenient means of immunizing animals with recombinant parasite antigens. DNA delivery methods are believed to affect the qualitative nature of immune responses to DNA vaccines in ways that may affect their protective activity. However, relatively few studies have directly compared immune responses to plasmids encoding the same antigens after injection by different routes. Therefore, the purpose of this study was to explore the influence of the route of administration on antibody responses to plasmids encoding antigens from the filarial nematode parasite Brugia malayi.MethodsFour B. malayi genes and partial genes encoding paramyosin (BM5), heat shock protein (BMHSP-70), intermediate filament (BMIF) and a serodiagnostic antigen (BM14) were inserted in eukaryotic expression vectors (pJW4303 and pCR™3.1). BALB/c mice were immunized with individual recombinant plasmids or with a cocktail of all four plasmids by intramuscular injection (IM) or by gene gun-intradermal inoculation (GG). Antibody responses to recombinant antigens were measured by ELISA. Mean IgG1 to IgG2a antibody ratios were used as an indicator of Th1 or Th2 bias in immune responses induced with particular antigens by IM or GG immunization. The statistical significance of group differences in antibody responses was assessed by the non-parametric Kruskal-Wallis test.ResultsMice produced antibody responses to all four filarial antigens after DNA vaccination by either the IM or GG route. Antibody responses to BM5 paramyosin were strongly biased toward IgG1 with lower levels of IgG2a after GG vaccination, while IM vaccination produced dominant IgG2a antibody responses. Antibody responses were biased toward IgG1 after both IM and GG immunization with BMIF, but antibodies were biased toward IgG2a after IM and GG vaccination with BMHSP-70 and BM14. Animals injected with a mixture of four recombinant plasmid DNAs produced antibodies to all four antigens.ConclusionsOur results show that monovalent and polyvalent DNA vaccination successfully induced antibody responses to a variety of filarial antigens. However, antibody responses to different antigens varied in magnitude and with respect to isotype bias. The isotype bias of antibody responses following DNA vaccination can be affected by route of administration and by intrinsic characteristics of individual antigens.

Differential expression of the msp1α gene of Anaplasma marginale occurs in bovine erythrocytes and tick cells

Major surface proteins (MSP) 1a and 1b of the tick-borne pathogen Anaplasma marginale (Rickettsiales: Anaplasmataceae) are conserved on A. marginale derived from bovine erythrocytes and tick cells. MSP1a and MSP1b form the MSP1 complex and are adhesins involved in infection of host cells. While both MSP1a and MSP1b are adhesins for bovine erythrocytes, only MSP1a is an adhesin for cultured and native tick cells. These studies were initiated because antibody responses to MSP1a and MSP1b differed in cattle immunized with killed A. marginale derived from bovine erythrocytes or cultured tick cells. A strong antibody response to MSP1a was observed in cattle immunized with erythrocyte-derived A. marginale, whereas cattle immunized with tick cell culture-derived A. marginale produced antibodies preferentially to MSP1b. The molecular basis of this differential antibody response was then studied using Western blot, confocal microscopy and reverse transcriptase (RT)-PCR. Whereas expression of MSP1b by A. marginale derived from both bovine and tick host cells was similar at the protein and RNA levels, expression of MSP1a by A. marginale in these cells differed. Low levels of MSP1a were observed in cultured tick cells and tick salivary glands, but high expression of MSP1a occurred on A. marginale derived from bovine erythrocytes. The analysis of the expression of the msp1α gene by RT-PCR suggests that the differential expression of MSP1a is regulated at the transcriptional level and may influence the infectivity of A. marginale for host cells. Variation in the expression of MSP1a may also contribute to phenotypic and antigenic changes in the pathogen.

Differential antibody responses to a distinct region of human papillomavirus minor capsid proteins

A peptide derived from the human papillomavirus type 16 (HPV-16) minor capsid protein, L2, has previously been reported to induce cross-neutralizing antibodies in mice. In this report, four HPV L2 peptides, including the HPV-16 peptide and its HPV type 6 and 11 homologues, along with extended peptides containing a conserved set of amino acids, were used to immunize rabbits and mice. Antibody responses were evaluated for specificity and ability to neutralize viral infection in vitro with a quantitative reverse transcriptase (RT)-polymerase chain reaction (PCR) assay. All peptide immunizations resulted in cognate and cross-peptide reactivity, but this did not translate equally into recognition of full-length protein, VLP, or neutralization of virus in vitro. This report provides the first evidence of cross-neutralization of authentic HPV by antiserum to L2 peptides. Comparison of the anti-peptide serum reactivity, especially with regard to neutralization of virus, indicates that the extended peptides may offer more potential to induce adequate responses for cross-protective immunity.

Differential Antibody Response of Cattle Immunized with Anaplasma marginale Derived from Bovine Erythrocytes or Cultured Tick Cells

Differential Antibody Response of Cattle Immunized with <i>Anaplasma marginale</i> Derived from Bovine Erythrocytes or Cultured Tick Cells

Growth phase of orally administered Lactobacillus strains differentially affects IgG1/IgG2a ratio for soluble antigens: implications for vaccine development

Lactobacillus strains with probiotic activity are major constituents of numerous common food products. Due to their ‘generally regarded as safe’-status (GRAS-status), Lactobacillus strains can also be genetically engineered for use in oral immunotherapeutic applications, such as vaccination and T lymphocyte tolerance induction in autoimmune disease. In the current study, we demonstrate that the growth phase of orally administered individual Lactobacillus strains can differentially affect antigen-specific antibody subclasses IgG1 and IgG2a, which might reflect skewing of systemic activity of T helper cell type 2 (Th2) and T helper cell type 1 (Th1) pathways, respectively. Mice were orally fed different wild type Lactobacillus strains in log phase or stationary phase and immunized intraperitoneally with a T-cell dependent protein antigen. Sera were evaluated for the ratio of antigen-specific IgG1 and IgG2a antibodies. Stationary Lactobacillus murines and Lactobacillus casei cultures, but not two other Lactobacillus strains, evoked significantly higher IgG1/IgG2a ratios than log phase cultures, possibly relating to increased activity of the Th2-pathway. Despite normal variation in antibody responses against TNP–CGG among individual mice, a high correlation was found between the IgG1 and IgG2a responses of mice within experimental groups. This differential antibody response is likely due to growth phase-dependent differences in bacterial cell composition. Since Lactobacillus growth phase dependent skewing of antibody responses possibly reflecting T-cell pathways can inadvertently affect allergic and (auto)-immune responses, the current findings strongly caution against unidimensional views on the oral administration of individual Lactobacillus strains for probiotic or immunotherapeutic purposes, but also suggest additional possibilities for immune modulation.

Antibody response to Mycobacterium tuberculosis 30 and 16kDa antigens in pulmonary tuberculosis with human immunodeficiency virus coinfection

There is urgent need for rapid diagnostic methods to identify tuberculosis among the HIV positive cases, since the mortality is high. We have isolated and evaluated the serodiagnostic potential of the 30kDa secreted antigen and 16kDa cytosolic antigen of M. tuberculosis, among the HIV-TB patients. Antibody response was studied using Enzyme linked immunosorbent assay. In the HIV-TB group, antibody was found to be 65%, 69% and 6% positive for IgG, A and M isotypes, respectively, against 30kDa. The sensitivity increased to 84%, upon combination of the results of 3 isotypes. Anti-16kDa was detected in 15% (G), 50% (A) and 3% (M) of cases. Combination of results improved the positivity to 57%. There was no difference in antibody response among the HIV-TB cases, related to CD4 counts. Thus the 30kDa antigen proved to be of diagnostic utility in HIV-TB.

Inactivated Hantaan virus vaccine derived from suspension culture of Vero cells

We have developed a cell culture-derived, inactivated vaccine against Hantaan virus for prevention of the hemorrhagic fever with renal syndrome (HFRS). Hantaan virus was purified from a microcarrier culture of Vero E6 cells by ultrafiltration and density gradient centrifugation. Viral infection was inactivated by treatment of the viral stock with formaldehyde. Immunogenic properties of the vaccine were characterized in comparison with Hantavax, a mouse brain-derived, formalin-inactivated vaccine that has been in human use for a decade in Korea. Compared to the Hantavax, immunization of Balb/c mice with the cell culture-based vaccine resulted in a moderate difference in antibody response to the viral nucleocapsid protein but more than five-fold increase in neutralizing activity. Moreover, all six mice immunized with 5 μg of the cell culture-based vaccine were fully protected from challenge with infectious virus, whereas virus was detected in lung and spleen of all animals immunized with the same dose of Hantavax. Four times higher dose of the latter vaccine was needed for complete protection. In the analysis of the humoral immune response to the vaccines, we found that all three viral structural proteins, N, G1 and G2 were immunoprecipitated by sera from animals immunized with the cell culture-based vaccine. In contrast, N and some G1 but no G2 were precipitated by the sera from animals immunized with Hantavax. These results suggest that the cell culture-based vaccine can provide more effective immunity than the Hantavax.

Analysis of B cell memory formation using DNA microarrays.

DNA microarray analysis of B cell subsets has identified comprehensive programs of gene expression that distinguish B cells at discrete stages of differentiation. The next task is to identify key genetic signals within these complex programs that regulate the dynamic cellular events during B cell activation in vivo. After stimulation with antigen, naïve B cells proliferate and differentiate, and then produce antibodies. Crucial qualitative differences in antibody responses are observed depending on whether or not B cells receive T cell help during activation. Proteins, lipopolysaccharides, and polysaccharides stimulate T-dependent (TD), T-independent type 1 (TI-1), and type 2 (TI-2) antibody responses, respectively. Only TD responses generate somatically mutated antibody-forming (plasma) cells and memory B cells, which produce high affinity anamnestic responses to subsequent antigen challenge. Somatic mutation of immunoglobulin genes occurs during B cell proliferation in germinal centres (GC), which are typical in TD responses but rare in TI responses. However, we have described a model, which is exceptional because numerous large GC form in response to a model TI-2 antigen, (4-hydoxy-3-nitrophenyl) acetyl (NP)-Ficoll. Significantly, these GC undergo involution before memory B cells are generated. This model provides an opportunity to investigate the genetic signals that drive memory cell formation, and we have compared global gene expression in TI and TD GC to identify a relatively small number of genes that are differentially expressed between the two prototypic B cell responses. This model demonstrates how genome-scale technology can be adapted to investigate specific aspects of B cell biology.

Alkaline Serine Proteinase from Aspergillus fumigatus Has Synergistic Effects on Asp-f-2-Induced Immune Response in Mice

Background: Exposure to Aspergillus fumigatus allergens results in the sensitization and the development of allergic bronchopulmonary aspergillosis in susceptible individuals. Aspergillus antigen consists of a number of chemically diverse components and their cumulative or synergistic effect may result in disease. When mice were challenged with individual recombinant allergens, there was only reduced inflammation and immunological responses compared to the whole antigen. Various enzymes identified from A. fumigatus have been thought to cause airway damage. In the present study, we evaluated the effect of exposure to Asp f 13, an alkaline serine proteinase, and Asp f 2 in mice. Methods: BALB/c mice were challenged intranasally with Asp f 2 and Asp f 13 alone and in combination. The antibody response, pulmonary inflammation, and airway hyperreactivity were studied. Results: Results demonstrated no major difference in antibody response and airway responses among the different groups. The inflammatory responses in the lungs, however, showed marked differences in the various groups. Conclusion: In spite of the similar immunological responses in the different groups of mice studied, the results demonstrate enhanced inflammation in the lungs of mice exposed to a combination of both allergens. Allergens with proteinase activity have been found to be involved in airway inflammation and remodeling, which may also apply for Aspergillus-induced allergy.

Safety and immunogenicity of 23-valent pneumococcal polysaccharide vaccine in HIV-1 infected former drug users

The immunogenicity of 23-valent pneumococcal polysaccharide vaccine was assessed in 57 HIV-1 infected former intravenous drug users and in 20 HIV-1 negative controls. The effect of vaccination on HIV-1 infection was studied in a subgroup of 38 patients, 60% of whom under highly active antiretroviral therapy (HAART). Antibody to capsular polysaccharides from Streptococcus pneumoniae serotypes 3, 4, 6B, 19F, 23F, and changes in CD4+ count, HIV-1 RNA, proviral DNA and HIV-1 phenotype were measured in pre- and post-vaccination samples. Vaccinations were well-tolerated. The rate of responders was higher ( P<0.05) in HIV-1 negative than in HIV-1 infected individuals. No difference in antibody response was found within HIV-1 infected patients stratified according to CD4+ counts. Post-vaccination antibody geometric mean concentrations (GMCs) to the five antigens were higher ( P<0.05) than baseline in HIV-1 negative subjects, but not in HIV-1 positive individuals. Those with CD4+ >500 cells/mm 3 showed a significant increase of antibody against type 3 only. Immunisation caused no significant changes in CD4+ counts and in either plasma HIV-1 RNA nor proviral DNA levels. Pneumococcal vaccination does not induce virological or immunological deterioration in HIV infected patients, but the antibody response to a single dose of vaccine is poor.

Differential cytokine and antibody responses to adult and larval stages of Onchocerca volvulus consistent with the development of concomitant immunity.

The possibility of concomitant immunity and its potential mechanisms in Onchocerca volvulus infection were examined by analyzing cytokine and antibody responses to infective larval (third-stage larvae [L3] and molting L3 [mL3]), adult female worm (F-OvAg), and skin microfilaria (Smf) antigens in infected individuals in a region of hyperendemicity in Cameroon as a function of age. Peripheral blood mononuclear cell interleukin 5 (IL-5) responses to F-OvAg and Smf declined significantly with age (equivalent to years of exposure to O. volvulus). In contrast, IL-5 secretion in response to L3 and mL3 remained elevated with increasing age. Gamma interferon responses to L3, mL3, and F-OvAg were low or suppressed and unrelated to age, except for responses to Smf in older subjects. IL-10 levels were uniformly elevated, regardless of age, in response to L3, mL3, and F-OvAg but not to Smf, for which levels declined with age. A total of 49 to 60% of subjects had granulocyte-macrophage colony-stimulating factor responses to all O. volvulus antigens unrelated to age. Analysis of levels of stage-specific immunoglobulin G3 (IgG3) and IgE revealed a striking, age-dependent dissociation between antibody responses to larval antigens (L3 and a recombinant L3-specific protein, O. volvulus ALT-1) which were significantly increased or maintained with age and antibody responses to F-OvAg, which decreased. Levels of IgG1 to L3 and F-OvAg were elevated regardless of age, and levels of IgG4 increased significantly with age, although not to O. volvulus ALT-1, which may have unique L3-specific epitopes. Immunofluorescence staining of whole larvae showed that total anti-L3 immunoglobulin levels also increased with the age of the serum donor. The separate and distinct cytokine and antibody responses to adult and infective larval stages of O. volvulus which are age related are consistent with the acquisition of concomitant immunity in infected individuals.

Identification of mechanisms of natural resistance to African trypanosomiasis in cattle

Natural resistance to African trypanosomiasis in certain Bos taurus cattle in West Africa, called trypanotolerance, may hold solutions for control of this economically crippling disease. Comparison of immune responses between trypanotolerant and trypanosusceptible cattle have shown some differences in antibody response, complement level and cytokine expression, but it is not known whether these differences are the cause of resistance. Two experiments were carried out to assess the contribution of the immune and haemopoietic systems to trypanotolerance. The production of haemopoietic chimaeras from trypanotolerant and susceptible twin calves and comparison of their responses after infection with singleton calves, allowed an assessment of the role of the haemopoietic system in trypanotolerance. An in vivo depletion of CD4 cells in the two breeds allowed an appraisal of the role of T and B lymphocytes in trypanotolerance. The results of the two experiments suggest that natural resistance comprises at least two mechanisms, an innate mechanism that controls parasite growth, and another, involving the haemopoietic system, that is able to limit anaemia. This supports the hypothesis that innate mechanisms in trypanotolerant cattle are more efficient in controlling disease, making them less reliant on antibody responses.

Differential antibody responses induced by Ara h 1 and patatin

Differential antibody responses induced by Ara h 1 and patatin