Small ruminant production in coffee-based mixed crop-livestock system of Western Ethiopian Highlands: Status and prospectus for improvement

The study was conducted in Goma district of Jimma Zone of Ethiopia with the objectives of documenting the reasons why farmers in coffee dominant mixed-farming systems of western Ethiopia keep small ruminants, and identifying the constraints and opportunities for improvement of this sector. Results are based on diagnostic survey of 160 sample households, group discussions and personal observation. The study district was stratified into three groups based on flock distribution as: sheep dominating, goat dominating and mixed flock sites. The average land holding per household was 1.93 ha. In Goma where coffee and chat are the major cash sources for farmers, small ruminant are also primarily kept for cash generation as reported by 94% of the sampled households. The second main reason for keeping small ruminant in the study area was for saving mainly in time of coffee failure. Keeping small ruminants as a source of manure was the third important reason. From the interviewed households, 59.4, 32.1, 23.5, and 19.4% of them utilize communal grazing, aftermath grazing, roadside grazing, and riverside grazing, respectively for their animal as a sources of feed. Most small ruminants are either tethered or herded all the seasons due to the cultivation of perennial crops and predators. All small ruminants are housed for protection from adverse weather conditions and predators. The major problems for small ruminant production and marketing were: feed and grazing land shortage, lack of input, predators, diseases and parasites and marketing problems. In order to exploit the current growing demand of small ruminant meat at local and international markets, research and development interventions are required with regard to the identification of alternative feed resources and strategic feeding management, identification of causes of diseases and their control methods and improving marketing efficiency through appropriate policy

IL-15 induces CD4(+) effector memory T cell production and tissue emigration in nonhuman primates

HIV infection selectively targets CD4(+) effector memory T (T(EM)) cells, resulting in dramatic depletion of CD4(+) T cells in mucosal effector sites in early infection. Regeneration of the T(EM) cell compartment is slow and incomplete, even when viral replication is controlled by antiretroviral therapy (ART). Here, we demonstrate that IL-15 dramatically increases in vivo proliferation of rhesus macaque (RM) CD4(+) and CD8(+) T(EM) cells with little effect on the naive or central memory T (T(CM)) cell subsets, a response pattern that is quite distinct from that of either IL-2 or IL-7. T(EM) cells produced in response to IL-15 did not accumulate in blood. Rather, 5-bromo-2′-deoxyuridine (BrdU) labeling studies suggest that many of these cells rapidly disperse to extralymphoid effector sites, where they manifest (slow) decay kinetics indistinguishable from that of untreated controls. In RMs with uncontrolled SIV infection and highly activated immune systems, IL-15 did not significantly increase CD4(+) T(EM) cell proliferation, but with virologic control and concomitant reduction in immune activation by ART, IL-15 responsiveness was again observed. These data suggest that therapeutic use of IL-15 in the setting of ART might facilitate specific restoration of the CD4(+) T cell compartment that is the primary target of HIV with less risk of exhausting precursor T cell compartments or generating potentially deleterious regulatory subsets

Cross-Species Rhesus Cytomegalovirus Infection of Cynomolgus Macaques.

Cytomegaloviruses (CMV) are highly species-specific due to millennia of co-evolution and adaptation to their host, with no successful experimental cross-species infection in primates reported to date. Accordingly, full genome phylogenetic analysis of multiple new CMV field isolates derived from two closely related nonhuman primate species, Indian-origin rhesus macaques (RM) and Mauritian-origin cynomolgus macaques (MCM), revealed distinct and tight lineage clustering according to the species of origin, with MCM CMV isolates mirroring the limited genetic diversity of their primate host that underwent a population bottleneck 400 years ago. Despite the ability of Rhesus CMV (RhCMV) laboratory strain 68-1 to replicate efficiently in MCM fibroblasts and potently inhibit antigen presentation to MCM T cells in vitro, RhCMV 68-1 failed to productively infect MCM in vivo, even in the absence of host CD8+ T and NK cells. In contrast, RhCMV clone 68-1.2, genetically repaired to express the homologues of the HCMV anti-apoptosis gene UL36 and epithelial cell tropism genes UL128 and UL130 absent in 68-1, efficiently infected MCM as evidenced by the induction of transgene-specific T cells and virus shedding. Recombinant variants of RhCMV 68-1 and 68-1.2 revealed that expression of either UL36 or UL128 together with UL130 enabled productive MCM infection, indicating that multiple layers of cross-species restriction operate even between closely related hosts. Cumulatively, these results implicate cell tropism and evasion of apoptosis as critical determinants of CMV transmission across primate species barriers, and extend the macaque model of human CMV infection and immunology to MCM, a nonhuman primate species with uniquely simplified host immunogenetics

Cytomegalovirus vectors expressing Plasmodium knowlesi antigens induce immune responses that delay parasitemia upon sporozoite challenge.

The development of a sterilizing vaccine against malaria remains one of the highest priorities for global health research. While sporozoite vaccines targeting the pre-erythrocytic stage show great promise, it has not been possible to maintain efficacy long-term, likely due to an inability of these vaccines to maintain effector memory T cell responses in the liver. Vaccines based on human cytomegalovirus (HCMV) might overcome this limitation since vectors based on rhesus CMV (RhCMV), the homologous virus in rhesus macaques (RM), elicit and indefinitely maintain high frequency, non-exhausted effector memory T cells in extralymphoid tissues, including the liver. Moreover, RhCMV strain 68-1 elicits CD8+ T cells broadly recognizing unconventional epitopes exclusively restricted by MHC-II and MHC-E. To evaluate the potential of these unique immune responses to protect against malaria, we expressed four Plasmodium knowlesi (Pk) antigens (CSP, AMA1, SSP2/TRAP, MSP1c) in RhCMV 68-1 or in Rh189-deleted 68-1, which additionally elicits canonical MHC-Ia-restricted CD8+ T cells. Upon inoculation of RM with either of these Pk Ag expressing RhCMV vaccines, we obtained T cell responses to each of the four Pk antigens. Upon challenge with Pk sporozoites we observed a delayed appearance of blood stage parasites in vaccinated RM consistent with a 75-80% reduction of parasite release from the liver. Moreover, the Rh189-deleted RhCMV/Pk vectors elicited sterile protection in one RM. Once in the blood, parasite growth was not affected. In contrast to T cell responses induced by Pk infection, RhCMV vectors maintained sustained T cell responses to all four malaria antigens in the liver post-challenge. The delayed appearance of blood stage parasites is thus likely due to a T cell-mediated inhibition of liver stage parasite development. As such, this vaccine approach can be used to efficiently test new T cell antigens, improve current vaccines targeting the liver stage and complement vaccines targeting erythrocytic antigens

Hepatocytic expression of human sodium-taurocholate cotransporting polypeptide enables hepatitis B virus infection of macaques.

Hepatitis B virus (HBV) is a major global health concern, and the development of curative therapeutics is urgently needed. Such efforts are impeded by the lack of a physiologically relevant, pre-clinical animal model of HBV infection. Here, we report that expression of the HBV entry receptor, human sodium-taurocholate cotransporting polypeptide (hNTCP), on macaque primary hepatocytes facilitates HBV infection in vitro, where all replicative intermediates including covalently closed circular DNA (cccDNA) are present. Furthermore, viral vector-mediated expression of hNTCP on hepatocytes in vivo renders rhesus macaques permissive to HBV infection. These in vivo macaque HBV infections are characterized by longitudinal HBV DNA in serum, and detection of HBV DNA, RNA, and HBV core antigen (HBcAg) in hepatocytes. Together, these results show that expressing hNTCP on macaque hepatocytes renders them susceptible to HBV infection, thereby establishing a physiologically relevant model of HBV infection to study immune clearance and test therapeutic and curative approaches

Natural Killer Cell Evasion Is Essential for Infection by Rhesus Cytomegalovirus

<div><p>The natural killer cell receptor NKG2D activates NK cells by engaging one of several ligands (NKG2DLs) belonging to either the MIC or ULBP families. Human cytomegalovirus (HCMV) UL16 and UL142 counteract this activation by retaining NKG2DLs and US18 and US20 act via lysomal degradation but the importance of NK cell evasion for infection is unknown. Since NKG2DLs are highly conserved in rhesus macaques, we characterized how NKG2DL interception by rhesus cytomegalovirus (RhCMV) impacts infection <i>in vivo</i>. Interestingly, RhCMV lacks homologs of UL16 and UL142 but instead employs Rh159, the homolog of UL148, to prevent NKG2DL surface expression. Rh159 resides in the endoplasmic reticulum and retains several NKG2DLs whereas UL148 does not interfere with NKG2DL expression. Deletion of Rh159 releases human and rhesus MIC proteins, but not ULBPs, from retention while increasing NK cell stimulation by infected cells. Importantly, RhCMV lacking Rh159 cannot infect CMV-naïve animals unless CD8+ cells, including NK cells, are depleted. However, infection can be rescued by replacing Rh159 with HCMV UL16 suggesting that Rh159 and UL16 perform similar functions <i>in vivo</i>. We therefore conclude that cytomegaloviral interference with NK cell activation is essential to establish but not to maintain chronic infection.</p></div

Deletion of Rh159 rescues intracellular transport and surface expression of MICA and MICB upon RhCMV infection.

<p><b>A)</b> Comparison of NKG2DL surface expression upon infection with RhCMV or ΔRh159. U373-NKG2DL cells were infected with RhCMV (blue) or ΔRh159 (red) (MOI = 3) for 48 h. Cell surface levels of NKG2DL or TfR were determined by flow cytometry, using specific antibodies and compared to isotype control (dotted). Depicted is NKG2DL or TfR surface expression on infected cells gated for RhCMV IE2⁺ expression. The results shown are representative of three or more independent experiments. <b>B)</b> Biosynthesis and maturation of NKG2DL in uninfected U373-NKG2DL cells or upon infection with RhCMV or ΔRh159. U373-NKG2DL cells were uninfected (NI), infected with RhCMV (WT) or ΔRh159 (MOI = 3) for 24 h, verified by light microscopy as having 100% CPE, then metabolically labeled with [35S]cysteine and [35S]methionine for 30 min prior to chasing the label for the indicated times. The indicated NKG2DLs were immunoprecipitated from cell lysates with specific mAbs. Immunoprecipitates were split and digested with EndoH (+) or mock treated (-) then analyzed by SDS-PAGE and autoradiography.</p