Newly designed primer sets available for evaluating various cytokines and iNOS mRNA expression in guinea pig lung tissues by RT-PCR

The guinea pig model for tick-borne spotted fever rickettsioses: A second look

The guinea pig (Cavia porcellus) has an established track record as an animal model, with its utility in rickettsial research documented as early as the turn of the 20th century. From identifying Rickettsia rickettsii as the agent of Rocky Mountain spotted fever and ticks as the natural transmission route to evaluating protective immunity and treatment for tick-borne rickettsiae, guinea pigs have been essential for advances in our understanding of spotted fever rickettsioses (SFR). Tick feeding on guinea pigs is feasible and results in transmission of tick-borne rickettsiae. The resulting infection leads to the recapitulation of SFR as defined by clinical signs that include fever, unthrift, and in the case of transmission by a Rickettsia parkeri-infected Amblyomma maculatum tick, a characteristic eschar at the site of the bite. No other small animal model recapitulates SFR, is large enough to collect multiple blood and skin samples for longitudinal studies, and has an immune system as similar to the human immune system. In the 1980s, the use of the guinea pig was significantly reduced due to advances made to the more reproductively prolific and inexpensive murine model. These advances included the development of genetically modified murine strains, which resulted in the expansion of murine-specific reagents and assays. Still, the advantages of the guinea pig as a model for SFR persist, novel assays are being developed to better monitor guinea pig immune responses, and tools, like CRISPR/Cas9, are now available. These technical advances allow guinea pigs to again contribute to our understanding of SFR. Importantly, returning to the guinea pig model with enhanced tools will enable rickettsial researchers to corroborate and potentially refine results acquired using mice. This minireview summarizes Cavia porcellus as an animal model for human tick-borne rickettsial diseases.

Augmentation of DTH reaction of mycobacterial antigenic cocktail using synthetic mycobacterial 19-kDa lipoprotein as a TLR-stimulant

The current study proposed that previously characterized individual antigenic proteins could represent potential replacement for conventional purified protein derivative (PPD) in tuberculosis skin testing when used in cocktails triggered by suitable TLR-stimulants that would provide the missing pro-inflammatory stimulus. Three different cocktails of previously selected antigens, including C1 (ESAT-6/CPF-10/MPB-83); C2 (ESAT-6/MPB-64/MPB-83); and C3 (CPF-10/MPB-64/MPB-83), were evaluated in vitro using lymphocytic proliferation and IFN-γ production assays, as well as mRNA and protein expression levels of TNF-α, IL-12p40, and IL-2 as pro-inflammatory molecules. C1 showed the highest significant induction of pro-inflammatory molecules as compared to other cocktails, yet still significantly lower than that induced by conventional PPD. Interestingly, inclusion of the synthetic Mycobacterium tuberculosis 19-kDa lipoprotein (Pam3Cys-SSNKSTTGSGETTTA) as a TLR-stimulant resulted in obvious augmentation of C1-induced pro-inflammatory molecules to levels comparable to that of PPD. In addition, skin testing using sensitized guinea pig model revealed comparable significant reaction to that of conventional PPD. ESAT-6/CPF-10/MPB-83 cocktail is suggested as a potential alternative skin-testing reagent when used in combination with the M. tuberculosis 19-kDa lipoprotein as a TLR-stimulant.

A Neglected Animal Model for a Neglected Disease: Guinea Pigs and the Search for an Improved Animal Model for Human Brucellosis

Brucellosis is a bacterial disease caused by species of the Brucella genus and affects a wide variety of domestic and wildlife species and is also an important zoonosis. The global burden of disease is difficult to assess but Brucella spp. have a worldwide distribution and are endemic in the Middle East, Africa, South America, and Asia. The clinical signs of fever and malaise are non-specific, and the available serological diagnostic tests lack a high degree specificity in endemic regions compared to other important public health diseases such as malaria. A better understanding of the pathogenesis of brucellosis through discoveries in animal models could lead to improved diagnostics and potentially a vaccine for human use. Mouse models have played an important role in elucidating the pathogenesis but do not replicate key features of the disease such as fever. Guinea pigs were instrumental in exploring the pathogenesis of brucellosis in the early nineteenth century and could offer an improvement on the mouse model as a model for human brucellosis.

Development and utilization of a custom PCR array workflow: analysis of gene expression in mycoplasma genitalium and guinea pig (Cavia porcellus)

Transcriptome analysis is a powerful tool for evaluating molecular pathways central to maturation of specific biological processes and disease states. Recently, PCR-based arrays have supplemented microarray and RNA-seq methodologies for studying changes in gene expression levels. PCR arrays are a more cost efficient alternative, however commercially available assemblies are generally limited to only a few more widely researched species (e.g., rat, human, and mouse). Consequently, the investigation of emerging or under-studied species is hindered until such assays are created. To address this need, we present data documenting the success of a developed workflow with enhanced potential to create and validate novel RT-PCR arrays for underrepresented species with whole or partial genome annotation. Utilizing this enhanced workflow, we have achieved a success rate of 80 % for first-round designs for over 400 primer pairs. Of these, ~160 distinct targets were sequence confirmed. Proof of concept studies using two unique arrays, one targeting the pathogenic bacterium Mycoplasma genitalium and the other specific for the guinea pig (Cavia porcellus), allowed us to identify significant (P < 0.05) changes in mRNA expression validated by subsequent qPCR. This flexible and adaptable platform provides a valuable and cost-effective alternative for gene expression analysis.

Efficacy of Mycobacterium indicus pranii immunotherapy as an adjunct to chemotherapy for tuberculosis and underlying immune responses in the lung

BACKGROUND

The 9-month-long chemotherapy of tuberculosis often results in poor compliance and emergence of drug-resistant strains. So, improved therapeutic strategy is urgently needed. Immunotherapy could be beneficial for the effective management of the disease. Previously we showed the protective efficacy of Mycobacterium indicus pranii (MIP) when given as prophylactic vaccine in animal models of tuberculosis.

METHODS

We sought to investigate whether MIP can be used as an adjunct to the chemotherapy in guinea pig models of tuberculosis. Efficacy of MIP was evaluated when given subcutaneously or by aerosol.

RESULTS

MIP-therapy as an adjunct to the chemotherapy was found to be effective in accelerating bacterial killing and improving organ pathology. MIP-immunotherapy resulted in higher numbers of activated antigen-presenting cells and lymphocytes in the infected lungs and also modulated the granulomatous response. Early increase in protective Th1 immune response was observed in the immunotherapy group. Following subsequent doses of MIP, decrease in the inflammatory response and increase in the immunosuppressive response was observed, which resulted in the improvement of lung pathology.

CONCLUSION

MIP immunotherapy is a valuable adjunct to chemotherapy for tuberculosis. Aerosol route of immunotherapy can play a crucial role for inducing immediate local immune response in the lung.

Latency antigen α-crystallin based vaccination imparts a robust protection against TB by modulating the dynamics of pulmonary cytokines

Background

Efficient control of tuberculosis (TB) requires development of strategies that can enhance efficacy of the existing vaccine Mycobacterium bovis Bacille Calmette Guerin (BCG). To date only a few studies have explored the potential of latency-associated antigens to augment the immunogenicity of BCG.

Methods/Principal Findings

We evaluated the protective efficacy of a heterologous prime boost approach based on recombinant BCG and DNA vaccines targeting α-crystallin, a prominent latency antigen. We show that “rBCG prime - DNA boost” strategy (R/D) confers a markedly superior protection along with reduced pathology in comparison to BCG vaccination in guinea pigs (565 fold and 45 fold reduced CFU in lungs and spleen, respectively, in comparison to BCG vaccination). In addition, R/D regimen also confers enhanced protection in mice. Our results in guinea pig model show a distinct association of enhanced protection with an increased level of interleukin (IL)12 and a simultaneous increase in immuno-regulatory cytokines such as transforming growth factor (TGF)β and IL10 in lungs. The T cell effector functions, which could not be measured in guinea pigs due to technical limitations, were characterized in mice by multi-parameter flow cytometry. We show that R/D regimen elicits a heightened multi-functional CD4 Th1 cell response leading to enhanced protection.

Conclusions/Significance

These results clearly indicate the superiority of α-crystallin based R/D regimen over BCG. Our observations from guinea pig studies indicate a crucial role of IL12, IL10 and TGFβ in vaccine-induced protection. Further, characterization of T cell responses in mice demonstrates that protection against TB is predictable by the frequency of CD4 T cells simultaneously producing interferon (IFN)γ, tumor necrosis factor (TNF)α and IL2. We anticipate that this study will not only contribute toward the development of a superior alternative to BCG, but will also stimulate designing of TB vaccines based on latency antigens.

Establishment of a guinea pig model of latent tuberculosis with GFP-introduced Mycobacterium tuberculosis

There exists latent tuberculosis, in which small numbers of tubercle bacilli remain viable in the host without visible granulomatous lesions. As few data exist on the mechanisms of latent tuberculosis, it is important to examine latent tuberculosis in terms of pathogenesis and efficacy of chemotherapy. As a first step, we used green fluorescent protein (GFP)-introduced H37Rv Mycobacterium tuberculosis to establish latent tuberculosis in the guinea pig that provides one of the best animal models of tuberculosis. We inoculated the guinea pigs subcutaneously with 100 or 1,000 colony-forming unit (CFU) of tubercle bacilli. During the 300-day follow-up period after infection, there were no clinical signs of disease, suggesting a lack of visible granulomatous lesions. In fact, upon necropsy, no macroscopic tuberculous lesions were recognized, but histopathological examination of the lung, spleen and liver revealed microgranulomas consisting of epithelioid macrophages and lymphocytes without central necrosis. Importantly, photon imaging visualized granulomatous lesions corresponding to these histologically apparent microgranulomas. Tuberculin skin testing of infected guinea pigs showed strong positivity (> or = 10 mm induration) until the end of the experiments. Real-time PCR analysis showed a significant increase in the expression levels of interferon-gamma, tumor necrosis factor-alpha, interleukin-12, and inducible nitric oxide synthase mRNAs in infected lung tissues after 300 days (P < 0.01). As human samples are hardly available to study latent tuberculosis, our guinea pig model would be useful for examining the pathogenesis and molecular mechanisms of latent tuberculosis as well as for monitoring the results of chemotherapy with green fluorescence emission of tubercle bacilli.

A specific induction of interleukin-10 by the Map41 recombinant PPE antigen of Mycobacterium avium subsp. paratuberculosis

Interleukin-10 (IL-10) is not only an essential immunoregulator in host immunity, but also it accounts for the intracellular survival of mycobacteria because of its inhibitory activity against anti-mycobacterial functions of macrophage. It has been also indicated that blood cells from calves infected with Mycobacterium avium subsp. paratuberculosis (Map) produce a large amount of IL-10 after stimulation with Map antigen, and it leads to suppression of Interferon-gamma (IFN-gamma) production in T-cells. This characteristic expression of IL-10 in Map-infected cattle seems to be playing important roles in the pathogenesis of Johne's disease caused by Map, and could be an important diagnostic indicator. The aim of this study was to investigate the diagnostic significance of IL-10 production from blood cells stimulated by a PPE (Proline-Proline-Glutamic acid) protein family of Map. The recombinant PPE protein, Map41, which has been reported as one of the IFN-gamma inducing antigens of Map, also strongly induced IL-10 from macrophages obtained from infected calves. The elicited IL-10 production in response to Map41 from experimentally infected calves was as early as 2 weeks after the inoculation of Map, and the IL-10 production was detected earlier than that of IFN-gamma. The blood cells from calves immunized with Map produced higher amounts of IL-10 against Map41 stimulation than those of calves immunized with various Mycobacterium species. Furthermore, this IL-10 induction also showed high specificity to Map in guinea pigs experimentally infected with various Mycobacterium species. These observations suggest that IL-10 assay is a useful diagnostic method in the early stage of Johne's disease.

Kinetics of the immune response profile in guinea pigs after vaccination with Mycobacterium bovis BCG and infection with Mycobacterium tuberculosis

The guinea pig model of tuberculosis is used extensively in assessing novel vaccines, since Mycobacterium bovis BCG vaccination effectively prolongs survival after low-dose aerosol infection with virulent M. tuberculosis. To better understand how BCG extends time to death after pulmonary infection with M. tuberculosis, we examined cytokine responses postvaccination and recruitment of activated T cells and cytokine response postinfection. At 10 weeks postvaccination, splenic gamma interferon (IFN-gamma) mRNA was significantly elevated compared to the levels at 5 weeks in ex vivo stimulation assays. At 15, 40, 60, and 120 days postinfection, T-cell activation (CD4+ CD62Llow and CD8+ CD62Llow) and mRNA expression of IFN-gamma, tumor necrosis factor alpha (TNF-alpha), interleukin-1 (IL-1), IL-10, IL-12, and eomesodermin were assessed. Our data show that at day 40, BCG-vaccinated guinea pigs had significantly increased levels of IFN-gamma mRNA expression but decreased TNF-alpha mRNA expression in their lungs compared to the levels in nonvaccinated animals. At day 120, a time when nonvaccinated guinea pigs succumbed to infection, low levels of IFN-gamma mRNA were observed even though there were increasing levels of IL-1, IL-12, and IL-10, and the numbers of activated T cells did not differ from those in BCG-vaccinated animals. BCG vaccination conferred the advantage of recruiting greater numbers of CD4+ CD62Llow T cells at day 40, although the numbers of CD8+ CD62Llow T cells were not elevated compared to the numbers in nonvaccinated animals. Our data suggest that day 40 postinfection may be a pivotal time point in determining vaccine efficacy and prolonged survival and that BCG promotes the capacity of T cells in the lungs to respond to infection.

Higher susceptibility of type 1 diabetic rats to Mycobacterium tuberculosis infection

An association between diabetes mellitus and tuberculosis has been implicated for a long time. We have previously reported that Goto Kakizaki type 2 diabetic rats are highly susceptible to Mycobacterium (M.) tuberculosis infection. As a next step, we attempted to clarify whether type 1 diabetic rats are more susceptible to M. tuberculosis than non-diabetic wild-type (WT) rats. Here, we used the Komeda diabetes-prone (KDP) rat, as a model of type 1 diabetes mellitus. The infected KDP rats developed large granulomas without central necrosis in their lungs, liver or spleen. This was consistent with a significant increase in the number of colony-forming units (cfu) of M. tuberculosis in the lungs and spleen (p < 0.01). Insulin treatment resulted in significant reduction of tubercle bacilli in the infected KDP rats (p < 0.01). Pulmonary levels of interferon-gamma, tumor necrosis factor-alpha and interleukin-1beta mRNAs were higher in the infected diabetic rats than in WT rats. Alveolar macrophages from KDP rats were not fully activated by M. tuberculosis infection because the macrophages did not secrete nitric oxide (NO) that can kill M. tuberculosis (p < 0.01), but no significant difference in phagocytosis of tubercle bacilli by alveolar macrophages was observed between KDP and WT rats. Taken together, our findings indicate that type 1 diabetic rats are more susceptible to M. tuberculosis that WT rats.

Enhanced and enduring protection against tuberculosis by recombinant BCG-Ag85C and its association with modulation of cytokine profile in lung

Background

The variable efficacy (0–80%) of Mycobacterium bovis Bacille Calmette Guréin (BCG) vaccine against adult tuberculosis (TB) necessitates development of alternative vaccine candidates. Development of recombinant BCG (rBCG) over-expressing promising immunodominant antigens of M. tuberculosis represents one of the potential approaches for the development of vaccines against TB.

Methods/Principal Findings

A recombinant strain of BCG - rBCG85C, over expressing the antigen 85C, a secretory immuno-dominant protein of M. tuberculosis, was evaluated for its protective efficacy in guinea pigs against M. tuberculosis challenge by aerosol route. Immunization with rBCG85C resulted in a substantial reduction in the lung (1.87 log₁₀, p<0.01) and spleen (2.36 log₁₀, p<0.001) bacillary load with a commensurate reduction in pathological damage, when compared to the animals immunized with the parent BCG strain at 10 weeks post-infection. rBCG85C continued to provide superior protection over BCG even when post-challenge period was prolonged to 16 weeks. The cytokine profile of pulmonary granulomas revealed that the superior protection imparted by rBCG85C was associated with the reduced levels of pro-inflammatory cytokines - interleukin (IL)-12, interferon (IFN)-γ, tumor necrosis factor (TNF)-α, moderate levels of anti-inflammatory cytokine - transforming growth factor (TGF)-β along with up-regulation of inducible nitric oxide synthase (iNOS). In addition, the rBCG85C vaccine induced modulation of the cytokine levels was found to be associated with reduced fibrosis and antigen load accompanied by the restoration of normal lung architecture.

Conclusions/Significance

These results clearly indicate the superiority of rBCG85C over BCG as a promising prophylactic vaccine against TB. The enduring protection observed in this study gives enough reason to postulate that if an open-ended study is carried out with low dose of infection, rBCG85C vaccine in all likelihood would show enhanced survival of guinea pigs.

Using guinea pigs in studies relevant to asthma and COPD

The guinea pig has been the most commonly used small animal species in preclinical studies related to asthma and COPD. The primary advantages of the guinea pig are the similar potencies and efficacies of agonists and antagonists in human and guinea pig airways and the many similarities in physiological processes, especially airway autonomic control and the response to allergen. The primary disadvantages to using guinea pigs are the lack of transgenic methods, limited numbers of guinea pig strains for comparative studies and a prominent axon reflex that is unlikely to be present in human airways. These attributes and various models developed in guinea pigs are discussed.

Retinoic acid therapy attenuates the severity of tuberculosis while altering lymphocyte and macrophage numbers and cytokine expression in rats infected with Mycobacterium tuberculosis

Because retinoic acid (RA) exerts a stimulatory effect on macrophages and tubercle bacilli target alveolar macrophages, the therapeutic potential of RA was examined in rats with tuberculosis. In the main study, 15 rats were randomized to treatment with oil (control) or RA, 100 microg/100 g body weight per dose, given 3 times weekly for 3 and 5 wk after infection with Mycobacterium tuberculosis strain H37Rv. There was a significant difference in the severity of tuberculosis histopathology between control and RA-treated rats, and oral administration of RA decreased the number of colony-forming units (CFU) in both lung and spleen at 3 and 5 wk after H37Rv infection (P < 0.005). CD4-positive and CD8-positive T cells, natural killer cells, and CD163-positive macrophages increased (P < 0.05) in the infected lung tissues of RA-treated rats. Expression of IFNgamma and inducible nitric oxide synthetase messenger RNA (mRNA) was higher in the infected lung tissues of RA-treated rats than in control rats. Alveolar macrophages from rats treated in vivo with RA and infected in vitro with M. tuberculosis showed significantly higher expression of TNFalpha and IL-1beta mRNA than macrophages in control rats. To our knowledge, this is the first reported study to demonstrate that orally administered RA significantly inhibits the in vivo growth of M. tuberculosis and the development of tuberculosis.

Cytokine profiles in primary and secondary pulmonary granulomas of Guinea pigs with tuberculosis

The cytokine mRNA profiles of primary (arising from inhaled bacilli) and secondary (arising from hematogenous reseeding of the lung) granulomas from the lung lobes of bacillus Calmette-Guérin (BCG)-vaccinated and unimmunized guinea pigs challenged with virulent Mycobacterium tuberculosis by the pulmonary route were assessed in situ using laser capture microdissection (LCM) at 6 weeks after infection. The challenge dose chosen was so low that some lung lobes did not receive an implant from the airway. In unimmunized guinea pigs, some lobes contained either large, necrotic primary lesions or small, non-necrotic secondary lesions, or both. The lobes of BCG-vaccinated animals contained only non-necrotic primary tubercles, and no secondary lesions were visible. Real-time PCR analysis of the acquired RNA clearly demonstrated that primary tubercles from BCG-vaccinated guinea pigs were overwhelmed with mRNA from the anti-inflammatory cytokine, transforming growth factor (TGF)-beta, with some IFN-gamma and IL-12p40 mRNA. In contrast, primary lesions from unimmunized animals were dominated by proinflammatory TNF-alpha mRNA. The cytokine mRNA profile of secondary lesions from unimmunized animals was strikingly similar to the profile of primary lesions from BCG-vaccinated guinea pigs (i.e., a predominance of TGF-beta mRNA with some IL-12p40 and IFN-gamma mRNA), indicating that the lung lobes from which these lesions were retrieved had been naturally "vaccinated" by the time the bloodborne bacilli returned to the lung at 3 to 4 weeks after infection. Furthermore, cytokine mRNA analysis of splenic granulomas from nonvaccinated and vaccinated animals showed close resemblance to primary granulomas recovered from the lungs of the same animal, that is, high levels of TNF-alpha mRNA in unimmunized animals, and mostly TGF-beta mRNA in BCG-vaccinated guinea pigs. Taken together, these data indicate that mycobacteria returning to the lungs of unimmunized guinea pigs 3 to 4 weeks after infection induce a local cytokine response that is fundamentally different from the response to inhaled bacilli and is reminiscent of the primary response in a vaccinated animal.

BCG vaccination enhances resistance to M. tuberculosis infection in guinea pigs fed a low casein diet

In order to examine the relationship between malnutrition and tuberculosis development in vivo, a malnourished guinea pig model fed with a low casein (5%) diet was developed. After being fed with the low casein diet, the guinea pigs were infected with Mycobacterium (M.) tuberculosis Kurono strain by aerosol infection, and seven weeks later were subjected to histopathologic examination, colony-forming unit (CFU) assay, fluorescence-activated cell sorter (FACS) analysis and real-time reverse transcriptase-polymerase chain reaction (RT-PCR) for interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha, interleukin (IL)-12 and inducible nitric oxide synthase (iNOS) mRNA. Another group of guinea pigs were vaccinated subcutaneously with 10(6) CFU BCG Tokyo for three weeks and then similarly infected by aerosol. Eighty-eight% (7/8) of the malnourished guinea pigs succumbed to mycobacterial infection within 85 days after infection, while the malnourished guinea pigs vaccinated with BCG Tokyo survived. CFU assay showed that lung and splenic CFUs were higher in the low casein diet-fed groups than in the control diet (20% casein)-fed groups, although both groups had significantly lower CFUs after vaccination with BCG Tokyo (p<0.01). Examination of lung histopathology revealed that pulmonary granulomas were large and disorganized in the groups fed the low casein diet. The number of visible lesions on the surfaces of the fixed lungs in guinea pigs fed control diet+BCG and low casein diet+BCG was low significantly. Pan T-, CD4-, CD8- and Mac antigen-positive cells were also recognized in the infected lung tissues of low casein-fed guinea pigs and Pan T-, CD4- and Mac antigen-positive cells increased after vaccination with BCG Tokyo. Expression of IFN-gamma, TNF-alpha, IL-12 and iNOS mRNA was also recognized in the infected lung tissues of low casein-fed guinea pigs and IFN-gamma and TNF-alpha mRNA expression was enhanced with BCG vaccination. These results indicate that malnutrition exacerbates mycobacterial infection and that malnourished infected hosts may be protected by BCG vaccination.

Protective efficacy of recombinant (Ag85A) BCG Tokyo with Ag85A peptide boosting against Mycobacterium tuberculosis-infected guinea pigs in comparison with that of DNA vaccine encoding Ag85A

A recombinant form of BCG Tokyo with an Ag85A gene insert was administered once subcutaneously to guinea pigs and its protective efficacy was compared with that of a DNA vaccine encoding Ag85A from Mycobacterium tuberculosis administered twice to guinea pigs by epidermal gene gun bombardment. Vaccination with either the recombinant BCG Tokyo or Ag85A DNA significantly reduced the severity of pulmonary pathology and the number of pulmonary and splenic colony-forming units (cfu) (p<0.001). The recombinant BCG Tokyo was better than Ag85A DNA in terms of protective efficacy against M. tuberculosis. When immunogenic synthetic Ag85A peptide was further used as a booster together with recombinant BCG Tokyo (Ag85A) or Ag85A DNA, lung pathology was improved significantly and the number of pulmonary CFU was reduced significantly. Neither recombinant BCG Tokyo, Ag85A DNA, nor the parental BCG Tokyo protected the guinea pigs from hematogenous spread of tubercle bacilli to the spleen because splenic granulomas without central necrosis were recognized. The spleen tissues from guinea pigs vaccinated with recombinant BCG Tokyo or Ag85A DNA expressed IFN-gamma and IL-2 mRNA at significantly high levels (p<0.001) as evaluated by reverse transcription polymerase chain reaction. It is concluded that peptide boosting is important for the induction of higher protective efficacy by recombinant BCG Tokyo or a tuberculosis DNA vaccine and both recombinant BCG Tokyo (Ag85A) and Ag85A DNA vaccine induce Th2 cytokine mRNA expression significantly.

Development of a guinea pig immune response-related microarray and its use to define the host response following Mycobacterium bovis BCG vaccination

Immune responses in the guinea pig model are understudied because of a lack of commercial reagents. We have developed a custom-made guinea pig oligonucleotide microarray (81 spots) and have examined the gene expression profile of splenocytes restimulated in vitro from Mycobacterium bovis BCG-vaccinated and naive animals. Eleven genes were significantly (P < 0.05) up-regulated following vaccination, indicating a Th1-type response. These results show that microarrays can be used to more fully define immune profiles of guinea pigs.

Effect of Dietary Administration of Bananas on Immunocytes in F1 Hybrid Calves

The effect of dietary administration of bananas on immunocytes in calves was investigated. Twenty Fl hybrid calves were used in this study (treated group n=10, control group n=10). Banana (2 g/kg BW) was administered to the calves for 5 days. Leukocyte subsets were examined on days 0, 5, 10, and 15. The numbers CD3+, (CD3+)CD45R-, and (CD3+)TcR+ cells significantly increased between day 0 and day 5 in the treated group (P<0.01), and were significantly higher on day 5 in the treated group relative to the control group (P<0.05). These data showed that feeding banana to calves increased T-lymphocytes, suggesting it might be possible to enhance protective functions against infections.