A standard PLVF toxicity study was performed in rabbits. Chinchilla male and female rabbits were purchased from the Federal State Budgetary Institution of Science “Scientific Center for Biomedical Technologies of the Federal Medical and Biological Agency”, Russia. Acute toxicity studies were performed with a single subcutaneous injection of 125 μg/0.5 mL of PLVF (5 male and 5 female rabbits per group, aged 3 months at the start of experiment and weighing 2708 ± 71 g), followed by observation for 14 days. Animals in the control group were injected with 0.5 mL of PBS. Chronic toxicity studies were performed with daily subcutaneous immunization of rabbits with 125 μg/0.5 mL PLVF for a week (5 males and 5 females per group), followed by observation for 7 days. Animals in the control group were injected with 0.5 mL of PBS. Blood samples for hematology and biochemistry were collected before vaccination, and 7 and 14 days after vaccination. On the 14th day after vaccination, necropsy, histological examination of 16 internal organs and tissues of each rabbit, and the blood differential test were performed. The local irritation was studied by histopathological evaluation of the site of repeated subcutaneous injection of the vaccine preparation (macro- and microscopic description of the skin at the injection site).
Tissue samples for histological examination were fixed in 10% neutral buffered formalin, dehydrated in ascending concentrations of alcohol, and embedded in paraffin. Paraffin sections 5 μm thick were cut on a SM 2000R microtome (Leica, Wetzlar, Germany), stained with hematoxylin and eosin, and examined using a DM1000 microscope (Leica, Wetzlar, Germany).
The study of acute and chronic toxicity, as well as the study of the local tolerance of PLVF, was carried out in accordance with the recommendations and the requirements of local legislation (Federal Law of 12.04.10 N 61 “On the Circulation of Medicines”).
Ledov V.A., Golovina M.E., Alkhazova B.I., Lvov V.L., Kovalchuk A.L, & Aparin P.G. (2023). A Pentavalent Shigella flexneri LPS-Based Vaccine Candidate Is Safe and Immunogenic in Animal Models. Vaccines, 11(2), 345.