Viability and Function in Lymphocytes Cultured from the Horse, Chicken, and Mouse: Effects of Different Leukocyte Enrichment Techniques

Impact of apitherapy on canine, equine, and chicken lymphocytes, in vitro

Apitherapy is a form of alternative medicine that utilizes products from the western honeybee (Apis mellifera), including honey, propolis, and honeybee venom, to improve the health status of human patients by altering host immunity. An added benefit of these products is that they are nutraceuticals and relatively inexpensive to aquire. Currently, little is known about the use of honeybee products in veterinary species, as well as their impact on host immunity. In the present in vitro study, honey, propolis, and honeybee venom were co-cultured with enriched canine, equine, and chicken peripheral blood lymphocytes (PBLs) with cell proliferation, cell viability/apoptosis, and cellular morphology evaluated. Concanavalin A (Con A) and dexamethasone were used as stimulatory and suppressive controls, respectively. Honeybee products' effects on the three veterinary species varied by product and the species. Honey stimulated the PBLs proliferation in all three species but also displayed some increased cytotoxicity. Propolis stimulated proliferation in canine and equine PBLs, however, it suppressed proliferation in the chicken PBLs. Honeybee venom was the strongest PBL stimulant for all three species and in the equine, surpassed the stimulant response of Con A and yet, enhanced PBL cell viability post culture. In summary, the results of this preliminary in vitro study show that these three honeybee products do impact lymphocyte proliferation and viability in dogs, horses, and chickens, and that more research both in vitro and in vivo will be necessary to draw conclusions regarding their future use as immune stimulants or inhibitors.

Variability in peripheral blood enrichment techniques can alter equine leukocyte cellularity, viability and function

Peripheral blood is commonly sampled to assess the health status of human and veterinary patients. Venous blood collection is a minimally invasive procedure, and in the horse, the common collection site is the jugular vein. Post blood collection, sample processing for leukocyte enrichment can vary by research laboratory with the potential to yield different effects on the enriched cells and their function. The focus of the present study was to compare a common blood dilution-leukocyte enrichment technique using a Histopaque gradient medium (His) to a modified leukocyte buffy coat syringe-lymphocyte separation medium technique (Syr- LSM) with peripheral blood from 12 healthy horses. The endpoints examined included cell recovery/mL of blood, cell viability, leukocyte enrichment purity, leukocyte cell marker subset phenotype, leukocyte spontaneous and mitogen-induced proliferation and secretory TNFα concentrations. Leukocyte cell recovery/mL of whole blood and cell viability was significantly increased in enriched leukocytes from the Syr-LSM technique. Interestingly, the percentage of CD8⁺ and CD21⁺ were significantly increased with the His technique as was Con A-induced proliferation. Still, leukocyte cell purity and TNFα concentrations from the 72 h cell culture supernatants were comparable across the two enrichment techniques. To summarize, the type of whole blood leukocyte enrichment technique employed can affect the results of immunologic assay endpoints possibly altering data interpretation.

Cannabinoids decrease the th17 inflammatory autoimmune phenotype

Cannabinoids, the Cannabis constituents, are known to possess anti-inflammatory properties but the mechanisms involved are not understood. Here we show that the main psychoactive cannabinoid, Δ-9-tetrahydrocannabinol (THC), and the main nonpsychoactive cannabinoid, cannabidiol (CBD), markedly reduce the Th17 phenotype which is known to be increased in inflammatory autoimmune pathologies such as Multiple Sclerosis. We found that reactivation by MOG35-55 of MOG35-55-specific encephalitogenic T cells (cells that induce Experimental Autoimmune Encephalitis when injected to mice) in the presence of spleen derived antigen presenting cells led to a large increase in IL-17 production and secretion. In addition, we found that the cannabinoids CBD and THC dose-dependently (at 0.1-5 μM) suppressed the production and secretion of this cytokine. Moreover, the mRNA and protein of IL-6, a key factor in Th17 induction, were also decreased. Pretreatment with CBD also resulted in increased levels of the anti-inflammatory cytokine IL-10. Interestingly, CBD and THC did not affect the levels of TNFα and IFNγ. The downregulation of IL-17 secretion by these cannabinoids does not seem to involve the CB1, CB2, PPARγ, 5-HT1A or TRPV1 receptors. In conclusion, the results show a unique cannabinoid modulation of the autoimmune cytokine milieu combining suppression of the pathogenic IL-17 and IL-6 cytokines along with boosting the expression of the anti-inflammatory cytokine IL-10.

Development of novel strategies for the isolation of piglet testis cells with a high proportion of gonocytes

Gonocytes have germline stem cell potential and are present in the neonatal testis, comprising 5–10% of freshly isolated testis cells. Maximising the number and proportion of gonocytes among freshly isolated testis cells will greatly facilitate their subsequent purification and in vitro study and manipulation. Seven experiments were conducted to evaluate the effects of multiple factors on the efficiency of testis cell isolation from neonatal pigs. We found that the use of a lysis buffer led to elimination of erythrocytes without adversely affecting testis cell isolation. Approximately ninefold as many live cells could be harvested by enzymatic digestion of testis tissues compared with mechanical methods. Digestion with collagenase–hyaluronidase–DNase followed by trypsin resulted in the highest recovery of live cells. However, the proportion of gonocytes (∼7%) did not differ between the mechanical and enzymatic methods of testis cell isolation. Pretreatment of the tissue with cold enzymes increased the recovery of live testis cells. New strategies of combining a gentle enzymatic digestion with two rounds of vortexing resulted in the isolation of testis cells with very high gonocyte proportion. The efficiency of these novel methods could be further optimised to collect testis cells with a gonocyte proportion of approximately 40%. This novel three-step testis cell isolation strategy can be completed within 1 h and can harvest approximately 17 × 106 live gonocytes per g testis tissue. Therefore, in addition to elucidating the effects of several factors on testis cell isolation, we developed a novel strategy for the isolation of testis cells that yielded approximately 40% gonocytes in the freshly isolated cells (i.e. four- to eight-fold higher than the proportions obtained using current strategies). This strategy has instant applications in the purification of gonocytes.