Seroprevalence and determinants of contagious bovine pleuropneumonia in cattle in Burkina Faso.

Contagious bovine pleuropneumonia (CBPP) is a bacterial disease caused by Mycoplasma mycoides subsp. Mycoides. This disease affects ruminants mainly cattle with respiratory disorders as predominant symptoms. In Burkina Faso, this condition has been considered as enzootic since several years but data on its seroprevalence remains scares. This study aimed to establish the serological prevalence and determinants of CBPP in Burkina Faso in 2017. For this purpose, 3969 serum samples have been collected following a stratified sampling plan based on vaccination coverage in 12 regions, 84 communes, and 210 villages and analyzed using c-ELISA test. Individual seroprevalence was 16.91% (95% CI: 15.74-18.07%), while 84.5% (95% CI: 60.46-80.02%) of communes, chosen as epidemiological units were found positive. The individual prevalence was found to be associated with agro-ecological area (p < 0.05) and a prevalence of 18.70% (95% CI: 16.74-20.66%) was noted in Sahelian areas, while 15.79% (95% CI: 14.34-17.23%) was found in Soudanian areas. The prevalence was also significantly associated with vaccination coverage (p < 0.05) with a prevalence of 13.92% (95% CI: 11.66-16.18%), 19.21% (95% CI: 16.66-20.75%) and 11.61%(95% CI: 9.00-14.23%) for high, moderate, and low vaccination coverage respectively. The individual prevalence was respectively 16.97 (95% CI: 15.56-18.39%) and 17.13% (95% CI: 15.93-18.33%) for female and animals more than 2 years old. According to regions, the highest seroprevalence was found in Plateau Central region (38.18%, 95% CI: 29.1-47.26%), while the lowest was found in Centre-Est Region (7%, 95% CI: 4.5-9.5%). These prevalence data will allow us to adapt the ongoing strategy to control CBPP in Burkina Faso.

Development of a Novel Cocktail Enzyme-Linked Immunosorbent Assay and a Field-Applicable Lateral-Flow Rapid Test for Diagnosis of Contagious Bovine Pleuropneumonia.

Contagious bovine pleuropneumonia (CBPP) is a severe respiratory disease that is widespread in sub-Saharan Africa. It is caused by Mycoplasma mycoides subsp. mycoides, a bacterium belonging to the Mycoplasma mycoides cluster. In the absence of an efficient CBPP vaccine, improved and easy-to-use diagnostic assays for recurrent testing combined with isolation and treatment of positive animals represent an option for CBPP control in Africa. Here we describe the comprehensive screening of 17 immunogenic Mycoplasma mycoides subsp. mycoides proteins using well-characterized bovine sera for the development of a novel cocktail enzyme-linked immunosorbent assay (ELISA) for laboratory use. Two recombinant Mycoplasma immunogens, MSC_0136 and MSC_0636, were used to set up a standardized cocktail ELISA protocol. According to the results from more than 100 serum samples tested, the sensitivity and specificity of the novel cocktail ELISA were 85.6% and 96.4%, respectively, with an overall diagnostic accuracy comparable to that of the Office International des Epizooties (OIE)-prescribed serological assays. In addition, we provide a proof of principle for a field-applicable, easy-to-use commercially produced prototype lateral-flow test for rapid (<30-min) diagnosis of CBPP.

A contagious bovine pleuropneumonia outbreak on a research farm in Ethiopia, and its dynamics over an eight-month period.

Contagious bovine pleuropneumonia (CBPP) was recognised on Bako Agricultural Research Farm, in the Oromia Region of Ethiopia, for the first time on 5 May 2011. The outbreak was investigated by combining recognition of clinical signs, post-mortem examination, mycoplasma isolation and serological testing using competitive enzymelinked immunosorbent assay (c-ELISA). The clinical cases were monitored for eight months; sick animals were treated with a range of antibiotics and isolated if necessary. The outbreak of CBPP was confirmed both bacteriologically and serologically and had spread to almost the entire herd (96.7%) within the eight-month observation period. Of the animals that recovered after antibiotic treatment, 12.3% fell sick again, showed typical signs of CBPP and were considered to be carriers. The role of treatment in the prevention of the spread of CBPP was minimal. Newly purchased animals that were not tested and quarantined before being introduced onto the farm were suspected to have been the most probable source of infection.

La péripneumonie contagieuse bovine (PPCB) a été détectée pour la première fois dans la Ferme de recherches agricoles de Bako, dans l'Oromia (Éthiopie) le 5 mai 2011. Des investigations ont été conduites sur le foyer, au cours desquelles ont été réalisés des examens cliniques, des autopsies, des tentatives d'isolement de mycoplasmes et des tests sérologiques recourant à l'épreuve immuno-enzymatique de compétition (c-ELISA). Les cas cliniques ont été suivis pendant huit mois. Les animaux atteints ont été traités par antibiothérapie et mis à l'isolement si nécessaire. Le diagnostic de PPCB a été confirmé par les résultats tant bactériologiques que sérologiques ; le foyer s'est propagé dans tout le troupeau (96,7 %) au cours des huit mois de la période d'observation. Parmi les animaux ayant réagi au traitement antibiotique, 12,3 % ont eu une rechute accompagnée de signes cliniques caractéristiques de PPCB et ont donc été considérés comme porteurs. Le traitement n'a pas permis de prévenir significativement la propagation de la PPCB. Des animaux achetés et introduits dans la ferme peu de temps avant l'apparition du premier cas, sans avoir été préalablement testés ni soumis à une quarantaine, constituent la source la plus probable de l'infection.

El 5 de mayo de 2001 se detectó por primera vez perineumonía contagiosa bovina en la Granja de Investigación Agrícola de Bako, sita en la región etíope de Oromia. Para estudiar el brote se combinó la observación de signos clínicos con la realización de necropsias, el aislamiento de micoplasmas y pruebas serológicas con un ensayo inmunoenzimático de competición (ELISAc). Durante ocho meses se hizo un seguimiento de los casos clínicos, y los animales enfermos fueron tratados con diversos antibióticos y aislados en caso necesario. Tanto bacteriológica como serológicamente se confirmó la presencia de un brote de perineumonía contagiosa bovina, que en el curso de los ocho meses de observación se había propagado a la casi totalidad del rebaño (96,7%). De los animales que se recobraron tras recibir terapia antibiótica, un 12,3% recayeron con signos típicos de la enfermedad y fueron considerados portadores. El tratamiento tuvo un efecto mínimo para prevenir la diseminación del brote. Según se piensa, lo más probable es que la infección tuviera su origen en un conjunto de animales recién adquiridos que a su llegada a la granja no fueron sometidos ni a pruebas de detección ni a cuarentena.

Morphological characterization and immunohistochemical detection of the proinflammatory cytokines IL-1ß, IL-17A, and TNF-α in lung lesions associated with contagious bovine pleuropneumonia.

Contagious bovine pleuropneumonia (CBPP), a severe respiratory disease, is characterized by massive inflammation of the lung especially during the acute clinical stage of infection. Tissue samples from cattle, experimentally infected with Mycoplasma mycoides subsp. mycoides Afadé, were subjected to histopathological and immunohistochemical examination in order to provide insight into innate immune pathways that shape inflammatory host responses. Lung lesions were characterized by vasculitis, necrosis, and increased presence of macrophages and neutrophils, relative to uninfected animals. The presence of three cytokines associated with innate inflammatory immune responses, namely, IL-1ß, IL-17A, and TNF-α, were qualitatively investigated in situ. Higher cytokine levels were detected in lung tissue samples from CBPP-affected cattle compared to samples derived from an uninfected control group. We therefore conclude that the cytokines TNF-α and IL-1ß, which are prevalent in the acute phase of infections, play a role in the inflammatory response seen in the lung tissue in CBPP. IL-17A gets released by activated macrophages and attracts granulocytes that modulate the acute phase of the CBPP lesions.

Vaccination of cattle with the N terminus of LppQ of Mycoplasma mycoides subsp. mycoides results in type III immune complex disease upon experimental infection.

Contagious bovine pleuropneumonia (CBPP) is a serious respiratory disease of cattle caused by Mycoplasma mycoides subsp. mycoides. Current vaccines against CBPP induce short-lived immunity and can cause severe postvaccine reactions. Previous studies have identified the N terminus of the transmembrane lipoprotein Q (LppQ-N') of M. mycoides subsp. mycoides as the major antigen and a possible virulence factor. We therefore immunized cattle with purified recombinant LppQ-N' formulated in Freund's adjuvant and challenged them with M. mycoides subsp. mycoides. Vaccinated animals showed a strong seroconversion to LppQ, but they exhibited significantly enhanced postchallenge glomerulonephritis compared to the placebo group (P = 0.021). Glomerulonephritis was characterized by features that suggested the development of antigen-antibody immune complexes. Clinical signs and gross pathological scores did not significantly differ between vaccinated and placebo groups. These findings reveal for the first time the pathogenesis of enhanced disease as a result of antibodies against LppQ during challenge and also argue against inclusion of LppQ-N' in a future subunit vaccine for CBPP.

Seroprevalence of contagious bovine pleuropneumonia (CBPP) in Mali.

A serological survey to determine the prevalence of contagious bovine pleuropneumonia (CBPP) in Mali was carried out by using the competitive enzyme linked-immunosorbent test (c-ELISA) on 8007 serum samples systematically collected from 199 cattle herds collected throughout the whole country. Results showed a national prevalence of 18.11 % at the individual level and 85.93 % at the herd level. Significant variations in the individual prevalence were observed between regions of the country and ranged from 4.63 % in Tombouctou to 54.88 % in Kidal. At the herd level, although there were variations between regions, a high prevalence was constantly observed ranging from 60 to 100 %, hence confirming the endemic nature of the disease across the country. The CBPP risk varied also between regions and was very low in Tombouctou (odds ratio (OR) = 0.4) but very high in Kidal (OR = 9.8). Similarly, the risk seemed higher in the animals of the over 3-year age group (OR = 1.6) compared to the other age groups. It was also observed that there was a slightly higher risk (OR = 1.3) in the females than in the males. This study confirms the presence of CBPP across the country and should help to elaborate strategies for the effective control of the disease.

Serological prevalence of contagious bovine pleuropneumonia in agro-pastoral areas of Nigeria.

BACKGROUND: Contagious bovine pleuropneumonia (CBPP), an infection of cattle caused by the small colony biotype of Mycoplasma mycoides subspecies mycoides (MmmSC), is a significant constraint to improved pastoral cattle productivity in sub-Saharan Africa. This cross-sectional study was aimed to estimate serological prevalence of CBPP and identify risk factors for herd sero-positivity within agro-pastoral areas of Nigeria. RESULTS: The herd level prevalence of CBPP was 54.7% (95% confidence interval (CI) = 47.7-62.0), and proportion of animals with detectable MmmSC monoclonal antibody was 30.2% (95% CI = 26.3-34.4). Herds were more likely to be sero-positive if they were potentially exposed to recent CBPP outbreaks (odds ratio (OR) = 4.9, 95% CI = 2.4-10.1) or of larger sizes (OR = 3.0, 95% CI = 1.2-7.5). Herds vaccinated against the disease had lower odds of being sero-positive (OR = 0.12, 95% CI = 0.02-0.6) than unvaccinated herds. CONCLUSIONS: CBPP is endemic to agro-pastoral areas, and it is doubtful if the current control strategies are making real impact in reducing production losses. Although eradication is more likely to be achieved through regional approaches, enhanced vaccination coverage supported with targeted surveillance and a trace back system based on cattle trade and movement records will sustain effective control of the disease in the Nigerian cattle population.

Interactions between Mycoplasma mycoides subsp. mycoides and bovine macrophages under physiological conditions.

We investigated the interactions of unopsonized and opsonized Mycoplasma mycoides subsp. mycoides (Mmm) with bovine macrophages in vitro. Mmm survived and proliferated extracellularly on bovine macrophage cell layers in the absence of Mmm-specific antisera. Bovine complement used at non-bactericidal concentrations did neither have opsonizing effect nor promoted intracellular survival, whereas Mmm-specific antisera substantially increased phagocytosis and Mmm killing. A phagocytosis-independent uptake of Mmm by macrophages occurred at a high multiplicity of infection, also found to induce the production of TNF, and both responses were unaffected by non-bactericidal doses of bovine complement. Bovine complement used at higher doses killed Mmm in cell-free cultures and completely abrogated TNF responses by macrophages. These results provide a framework to identify Mmm antigens involved in interactions with macrophages and targeted by potentially protective antibodies and point towards a pivotal role of complement in the control of inflammatory responses in contagious bovine pleuropneumonia.

Development of an improved vaccine for contagious bovine pleuropneumonia: an African perspective on challenges and proposed actions.

Contagious bovine pleuropneumonia (CBPP) caused by Mycoplasma mycoides subsp. mycoides (Mmm) is an economically very important cattle disease in sub-Saharan Africa. CBPP impacts animal health and poverty of livestock-dependent people through decreased animal productivity, reduced food supply, and the cost of control measures. CBPP is a barrier to trade in many African countries and this reduces the value of livestock and the income of many value chain stakeholders. The presence of CBPP also poses a constant threat to CBPP-free countries and creates costs in terms of the measures necessary to ensure the exclusion of disease. This opinion focuses on the biomedical research needed to foster the development of better control measures for CBPP. We suggest that different vaccine development approaches are followed in parallel. Basic immunology studies and systematic OMICs studies will be necessary in order to identify the protective arms of immunity and to shed more light on the pathogenicity mechanisms in CBPP. Moreover a robust challenge model and a close collaboration with African research units will be crucial to foster and implement a new vaccine for the progressive control of this cattle plague.

Seroprevalence of contagious bovine pleuropneumonia at export quarantine centers in and around Adama, Ethiopia.

A cross sectional study was undertaken from October 2010 to March 2011 to determine the seroprevalence of contagious bovine pleuropneumonia (CBPP) and its related risk factors in export quarantine centers. A total of 3,111 cattle sera were collected from different export quarantine farms located in and around Adama, namely, Bekero, Jogo, Kedir, and Dera farms, and tested for the presence of Mycoplasma mycoides subsp. mycoides small colonies antibody using competitive enzyme-linked immunosorbant assay. Of the total 3,111 cattle sera examined, 124 (4 %) were found positive for CBPP. Among the potential predisposing factors assessed, origin, transportation condition, confinement level, and stay time of the animals in quarantine center were not found significantly (P > 0.05) associated with the occurrence of the disease. Whereas age was found significantly (P < 0.05) associated with the occurrence of the disease in which a high seroprevalence was recorded in aged (9.5 %) animals than young (3 %). Generally, this study showed that CBPP is a threat for Ethiopian livestock export market and a well established disease in Borana and Bale areas, where the animals originated.

Caprine pleuropneumonia in Beetal goats [corrected].

Seroprevalence, clinical findings, and lesions of contagious caprine pleuropneumonia (CCPP) in Beetal goats were recorded during an outbreak. The overall seroprevalence of CCPP was 32.50%. Confirmation of Mycoplasma mycoides in serum was carried out using counter immunoelectrophoresis (CIE) technique. The highest CIE-positive cases were recorded in the older goats (51.72%) as compared to young ones. Nasal swabs collected from 39 goats showing respiratory signs were found positive for M. mycoides. The most consistent clinical findings were mild to severe cough, purulent nasal secretion, emaciation, dyspnea, increased respiration rate, and pyrexia. Mortality due to CCPP was 9.17%. Consolidation of lungs exhibited the highest frequency (100%), followed by alveolar exudation (90.90%) and pleural adhesion (72.72%). Among the microscopic lesions, septal peribronchiolar fibrosis exhibited the highest frequency (81.81%), followed by fibrinous pleuritis (63.63%) and peribronchiolar cuffing of mononuclear cells (54.54%) in lungs. From these results, it was concluded that CCPP under subtropical conditions has high prevalence in Beetal goats and leads to significant mortality.

A minor role of CD4+ T lymphocytes in the control of a primary infection of cattle with Mycoplasma mycoides subsp. mycoides.

Contagious bovine pleuropneumonia (CBPP), caused by Mycoplasma mycoides subsp. mycoides, is an important livestock disease in Africa. The current control measures rely on a vaccine with limited efficacy and occasional severe side effects. Knowledge of the protective arms of immunity involved in this disease will be beneficial for the development of an improved vaccine. In previous studies on cattle infected with M. mycoides subsp. mycoides, a correlation was detected between the levels of mycoplasma-specific IFN-γ-secreting CD4+ T lymphocytes and reduced clinical signs. However, no cause and effect has been established, and the role of such cells and of protective responses acquired during a primary infection is not known.We investigated the role of CD4+ T lymphocytes in CBPP by comparing disease patterns and post mortem findings between CD4+ T cell depleted and non-depleted cattle. The depletion was carried out using several injections of BoCD4 specific murine monoclonal antibody on day 6 after experimental endotracheal infection with the strain Afadé. All cattle were monitored clinically daily and sacrificed 28-30 days post-infection. Statistically significant but small differences were observed in the mortality rate between the depleted and non-depleted animals. However, no differences in clinical parameters (fever, signs of respiratory distress) and pathological lesions were observed, despite elimination of CD4+ T cells for more than a week. The slightly higher mortality in the depleted group suggests a minor role of CD4+ T cells in control of CBPP.

Comparison of complement fixation test, competitive ELISA and LppQ ELISA with post-mortem findings in the diagnosis of contagious bovine pleuropneumonia (CBPP).

The complement fixation test (CFT), the c-ELISA and an indirect LppQ ELISA were compared to post-mortem (PM) inspection for the diagnosis of contagious bovine pleuropneumonia (CBPP). Sera from 797 cattle in the CBPP affected area of Kazungula, Zambia and 202 sera from Lusaka, Zambia, a CBPP-free area were used. The clinical history of CBPP was recorded and all the cattle from Kazungula were slaughtered and PM inspections conducted. The prevalence of CBPP in Kazungula was 67.5% (95%CI 67.2%, 70.8%), 52.6% (95%CI 49.2%, 56.2%), 59.0% (95%CI 55.5%, 62.4%) and 44.4% (95%CI 41.0%, 47.9%) using PM inspection, CFT, c-ELISA and LppQ ELISA, respectively. Three of the 202 negative control animals tested positive on the c-ELISA although they were from a known CBPP negative zone. In this study, the c-ELISA was more sensitive in detecting cattle with lesions in the chronic stage than any other test whilst the CFT detected more during the onset stage. No single serological test could detect all stages of CBPP infection, therefore the use of more than one test is advised.

Assessing the effectiveness of intubation as a challenge model in contagious bovine pleuropneumonia vaccine experiments.

A study was carried out to assess the effectiveness of a bronchoscope in administering a pathogenic field strain of Mycoplasma mycoides subsp. mycoides (MmmSC) in cattle challenge experiments. Out of 16 animals inoculated using the bronchoscope, 10 (62.2%) showed clinical disease as evidenced by fever and 15 (93.8%) displayed typical lesions of CBPP from which MmmSC was isolated. Serum samples collected weekly were tested by Complement Fixation Test (CFT) and competitive enzyme-linked immunosorbent assay (c-ELISA). Antibodies to MmmSC were detected in 10 out of the 16 animals by the CFT and 11 out of the 16 animals by c-ELISA. The onset of clinical disease was as early as 2 days post-inoculation, and most of the animals developed clinical disease 2 to 3 weeks post-infection. These results clearly demonstrate that nasotracheal inoculation of pathogenic strain of MmmSC with the aid of a bronchoscope can lead to early onset of clinical disease; similar to previous studies but with higher numbers of animals showing clinical disease. This is in contrast with previous studies where early clinical disease was observed in as little as 15% of inoculated animals. This nasotracheal inoculation method using a bronchoscope can, therefore, be adopted for use in experimental challenge infections of cattle. This method is found to be a better replacement to the contact transmission method whose drawback includes extra cost of donor animals and unpredictable rate and timing of transmission from intubated to challenge animals.

Identification of genes coding for B cell antigens of Mycoplasma mycoides subsp. mycoides Small Colony (MmmSC) by using phage display.

BACKGROUND: Contagious bovine pleuropneumonia (CBPP) is a mycoplasmal disease caused by Mycoplasma mycoides subsp. mycoides SC (MmmSC). Since the disease is a serious problem that can affect cattle production in parts of Africa, there is a need for an effective and economical vaccine. Identifying which of the causative agent's proteins trigger potentially protective immune responses is an important step towards developing a subunit vaccine. Accordingly, the purpose of this study was to determine whether phage display combined with bioinformatics could be used to narrow the search for genes that code for potentially immunogenic proteins of MmmSC. Since the production of IgG2 and IgA are associated with a Th1 cellular immune response which is implicated in protection against CBPP, antigens which elicit these immunoglobulin subclasses may be useful in developing a subunit vaccine. RESULTS: A filamentous phage library displaying a repertoire of peptides expressed by fragments of the genome of MmmSC was constructed. It was subjected to selection using antibodies from naturally- and experimentally-infected cattle. Mycoplasmal genes were identified by matching the nucleotide sequences of DNA from immunoselected phage particles with the mycoplasmal genome. This allowed a catalogue of genes coding for the proteins that elicited an immune response to be compiled. Using this method together with computer algorithms designed to score parameters that influence surface accessibility and hence potential antigenicity, five genes (abc, gapN, glpO, lppB and ptsG) were chosen to be expressed in Escherichia coli. After appropriate site-directed mutagenesis, polypeptides representing portions of each of these proteins were tested for immunoreactivity. Of these five, polypeptides representing expression products of abc and lppB were recognised on immunoblots by sera obtained from cattle during a natural outbreak of the disease. CONCLUSION: Since phage display physically couples phenotype with genotype, it was used to compile a list of sequences that code for MmmSC proteins bearing epitopes which were recognised by antibodies in the serum of infected animals. Together with the appropriate bioinformatic analyses, this approach provided several potentially useful vaccine or diagnostic leads. The phage display step empirically identified sequences by their interaction with antibodies which accordingly reduced the number of ORFs that had to be expressed for testing. This is a particular advantage when working with MmmSC since the mycoplasmal codon for tryptophan needs to be mutated to prevent it from being translated as a stop in E. coli.

Contagious bovine pleuropneumonia: a rationale for the development of a mucosal sub-unit vaccine.

Contagious bovine pleuropneumonia (CBPP) remains a major cattle disease in Africa with serious socio-economic consequences. Its eradication requires the development of improved vaccines. Knowledge on this disease and its causing agent, Mycoplasma mycoides subsp. mycoides biotype Small Colony (MmmSC), has been progressing significantly in the last years, opening new areas for vaccine design. Advances were achieved in the understanding of the protective immune responses to MmmSC infection and immunopathological mechanisms allowing the pathogen to escape the host immune response. Based on sequencing and genomic studies, some virulence factors and metabolic pathways were unraveled leading to the identification of potential MmmSC vaccine candidates. Based on these findings, this review presents a scientific strategy to design multi-component sub-unit vaccines for mucosal delivery as the most promising approach for efficient long-term protective vaccines to prevent CBPP.

Assessment of in vitro interferon-gamma responses from peripheral blood mononuclear cells of cattle infected with Mycoplasma mycoides ssp. mycoides small colony type.

Contagious bovine pleuropneumonia (CBPP) is a lung disease caused by the bacterial pathogen Mycoplasma mycoides ssp. mycoides small colony type (MmmSC). It has been spreading due to a number of factors including poor vaccine efficacy and poor sensitivity of current diagnostic tests. The purpose of this study was to assess interferon gamma (IFN-gamma) release after stimulation of peripheral blood mononuclear cells (PBMC) from experimentally infected cattle. PBMC collected from 15 artificially infected animals were incubated with different concentrations of total MmmSC antigen. After 72h of incubation the IFN-gamma release was measured and found to be elevated in 11 animals. We did not observe a correlation between IFN-gamma release of animals with and without pathomorphological gross lesions. Therefore, our data do not confirm a role for CD4 T-lymphocytes in protection, since there is no correlation between IFN-g secretion (supposed to be mainly derived from CD4 T-cells) and disease severity. Additionally, we applied immunocytochemistry on affected lung tissue and detected no build up of T-lymphocytes (CD4 T-cells, CD8 T-cells) but a high presence of myeloid cells.

Identification of targets of monoclonal antibodies that inhibit adhesion and growth in Mycoplasma mycoides subspecies mycoides.

Mycoplasma mycoides subspecies mycoides (Mmm) adhesion is tissue and host specific. Inhibition of adhesion will prevent Mmm from binding to lung cells and hence prevent colonization and disease. The aim of this study was to develop a panel of Mmm monoclonal antibodies against Mmm and use these antibodies to investigate their inhibitory effect on the adherence of Mmm to bovine lung epithelial cells (BoLEC), and to further identify an antigen to any of the inhibitory antibodies. Thirteen anti-Mycoplasma mycoides subsp. mycoides (AMMY) monoclonal antibodies (mAbs) inhibited adhesion by at least 30% and ten of the mAbs bound to multiple bands on Western blots suggesting that the antibodies bound to proteins of variable sizes. AMMY 10, a previously characterized Mmm- capsular polysaccharide (CPS) specific antibody, inhibited growth of Mmm in vitro and also caused agglutination of Mmm total cell lysate. AMMY 5, a 2-oxo acid dehydrogenase acyltransferase (Catalytic domain) (MSC_0267) specific antibody, was identified and polyclonal rabbit serum against recombinant MSC_0267 blocked adhesion of Mmm to BoLEC by 41%. Antigens recognized by these antibodies could be vaccine candidate(s) and should be subsequently tested for their ability to induce a protective immune response in vivo.

Field trial of a combined vaccine against caprine contagious agalactia: humoral immune response in lactating goats.

Two vaccines against Mycoplasma agalactiae and Mycoplasma mycoides subsp. mycoides (large colony type) were developed using inactivated strains selected in previous characterization studies. Formaldehyde and phenol were used as the inactivating agents for vaccines A and B, respectively. Aluminium hydroxide plus purified saponin (Quil-A) were added to both vaccines as adjuvant. The field trial was designed to evaluate the specific humoral immune response to the two mycoplasma species in lactating goats over a period of 7 months. The vaccines were tested on 120 goats randomly assigned to three groups of 40 animals each. Two groups received two injections of vaccine A or B respectively, and a third group remained in the herd as control. Antibody titres determined by ELISA indicated a significant difference between both vaccines and the control group over a 6-month period. Immunoblotting assays also revealed the production of antibodies against the two mycoplasma species. Further field trials are underway to evaluate the efficacy and protection conferred to the animals by these specific antibodies.

Clinical, humoral and IFNgamma responses of cattle to infection with Mycoplasma mycoides var. mycoides small colony and attempts to condition the pathogenesis of the infection.

Contagious bovine pleuropneumonia (CBPP), caused by Mycoplasma mycoides var. mycoides small colony (MmmSC), is one of the most important diseases of cattle in Africa. The role of innate or acquired cell mediated and humoral immunity in conferring protection against MmmSC infection has not yet been elucidated. On the other hand, the pathological lesions caused by the aetiological agent have been considered indicative of an immunopathological process. In this study ten naïve cattle were exposed to in-contact infection with animals infected by intubation with a strain of MmmSC. Clinical signs, antibody response, IFNgamma release and pathological changes at necropsy were analysed and compared with the events following in-contact infection of an equal number of animals kept under daily treatment with cyclosporine for the entire observation period of 84 days. Cyclosporine is a suppressor of the immune response related to the T-cell system. Under the conditions of the experiment, cyclosporine appeared to condition the pathogenesis of CBPP by delaying the events that follow infection, bringing further support to the possibility that the immune response may have an impact on the disease outcome.