Comparing Intradermal (ID) Rabies Vaccination with Conventional IM Regimen on Humoral Response of New Zealand White Rabbits for the Production of Animal-Derived Polyclonal Antibodies.

In developing countries, it is imperative to implement cost-effective strategies for animal humoral response development in the production of antiserum. This study compared the effect of immunization regimens on the humoral immune response of New Zealand White (NZW) rabbits (N = 24) using cell culture rabies vaccine (CCRV) through intradermal (ID) and traditional intramuscular (IM) routes. The rabbits were divided into three experimental groups: (a) IPC-R2 with a two-site one-week regimen; (b) TRC-R3 with a two-site twenty-eight-day regimen; and (c) Alternate-R4 with a four-site one-week regimen. These regimens were then compared to the standard IM schedule of five doses of rabies vaccine administered at days 0, 3, 7, 14, and 28 in control group R-1. The results were evaluated at days 14 and 35 postvaccination using rabies-specific Platelia II™ ELISA kit method. The results showed a better response to the ID regimen than the IM route regarding immunogenicity and volume consumption of the vaccine. The three selected ID regimes showed significantly higher mean titer values than the control IM regimen group R-1 (p < 0.001). The study aims to explore simple immunization strategies to enhance the RV-specific antibody titers for immunization donor animals. This method would produce polyclonal antibodies and strengthen local production of polyclonal antibodies in Pakistan to deal with vaccine and rabies immunoglobulin (RIG) shortage, thus providing effective postexposure prophylaxis (PEP) for better control of rabies in developing countries.

Immune-adjuvant effect of vitamin A and probiotics supplementation on humoral response to cell culture rabies vaccine in rabbits.

This study was carried out to evaluate the effects of vitamin A (Vit A) and probiotic co-supplementation with rabies vaccine on humoral immune response in New Zealand white (NZW) rabbits. For this experiment, 54 rabbits were randomized into six experimental and three control groups. Mixed cultures of commercial probiotics supplements and a dose of Vit A were administered to each animal. Results were compared with the control group fed with only basal diet. Animals in different treatment groups showed significantly higher sero-conversions against rabies vaccine. There was a significant increase (p < 0.001) in the titers of rabies antibodies in all treatment groups on 14th and 35th days than control C3 group. Both commercial probiotics irrespective of brand increase the humoral immune response of rabbits against rabies vaccine. The mean titer values of all groups G1-G6 and sub-controls (C1, C2) were generally above 3.6 EU/ml on day 14th and between 3.7 and 3.9 EU/ml, showing highest sero-conversion on 35th day than mean titer of C3 control = 3.091 and 3.505 EU/ml respectively on both days. The maximum titer values were obtained with the addition of organic carrots to the daily diet. These results suggest that simple dietary interventions using probiotics and Vit A in natural form may enhance the efficacy of rabies vaccine in the host. These cost-effective strategies can be applied for getting higher yields of polyclonal antibody production in animal models, thus providing promising means of improving the final product yield and can be adopted easily by the manufacturers.

Evaluation of different Pakistani medicinal plants for inhibitory potential against Echis carinatus induced Phospholipase A2 toxicity.

Medicinal plants of Pakistan are known for their curative properties against snake bite as rural people have been using natural herbs for such injuries for hundreds to thousands of years. People of rural areas of Pakistan are prone to snakebite, and on the whole death due to snakebite has been increasing worldwide. The objective of this study was to test the neutralizing potential of 17 Pakistani medicinal plant extracts against phospholipase A2 activity in Echis carinatus venom. Plant material was extracted by simple maceration and fractionation of active plant extracts. Venom was collected by manual massage of the venom glands. The PLA2 enzymatic assay was performed to map out the venomous activity of Echis carinatus envenomation. Snake venom released fatty acids at different concentrations (0.1-5 mg/ml) of venom in a dose-dependent manner. Reduction of pH by 01 correlated with 133 µmol of fatty acids released at 5mg/ml of venom. All plants extract inhibited PLA2 activity, however, Curcuma longa, Citrullus colocynthis and Rubia cordifolia inhibited maximum of PLA2 activity (⁓78%) comparable to the standard antidote (p>0.5). Medicinal plants possess secondary metabolites and many active compounds that may have neutralizing or inhibiting properties against the PLA2 activity of Echis venom. Further studies such as compound analysis could provide an alternative against snakebites injuries resulting from Echis carinatus venom.