Ingelvac prrs mlv

MARC-145 cells were maintained in Modified Eagle's medium (MEM) supplemented with 7% fetal bovine serum (FBS) containing 100 U penicillin/mL and 100 μg streptomycin/mL at 37°C with 5% CO₂. Virus stocks were prepared and titered in MARC-145 cells and stored in aliquots at −80°C until use. For virus infection and titration, MEM supplemented with 2% FBS was used. PRRS modified live virus vaccine (Ingelvac PRRS MLV) was purchased from Boehringer Ingelheim Vetmedica Inc. PRRSV strains VR-2332, KS-06-72109 (KS-06), and NVSL97-7895 have been described previously [11 , 12 (link)].

Type 2 PRRSV FJZ03 strain (GenBank ID: KP860909) was isolated from lung samples of an aborted fetus in 2013 and FJWQ16 strain (GenBank ID: KX758249) from a herd with high morbidity and mortality in sows and piglets respiratory disease, in 2015. PRRSV was isolated from the positive sera and tissues using MARC-145 cells and real-time RT-PCR analysis was applied on the supernatants to confirm the growth of the virus. The virus-infected cells in 6-well plates were determined by indirect fluorescent antibody assay (IFA). The cell cultures were subjected to the extraction of total RNA using a viral nucleic extraction kit (TIANGEN, China). Nine overlapped fragments covering the whole genome were amplified by RT-PCR as previously described³² . Recombinant clones were sequenced by Ruibo Life Technologies Corporation (Beijing, China).
Modified live virus (MLV) vaccines based off VR-2332 (Ingelvac PRRS MLV) from Boehringer Ingelheim Vetmedica, Inc. Strains FJZ03 and FJWQ16 have been passaged 3 times in MARC-145 cells for use in the swine study.

PEDV NK94P6 and Fukuoka-1 Tr(−) strains which belong to classical clade (G1) were propagated in Vero-KY5 (Vero) cells. Trypsin was not used to culture PEDV in Vero cells. The NK94P6 and Fukuoka-1 strains were kindly provided by the National Institute of Animal Health, Japan, and the Fukuoka Chuo Livestock Hygiene Service Center, Fukuoka, Japan, respectively. The Vero cells were also provided by the National Institute of Animal Health, Japan. Briefly, Vero cells were cultured in Eagle’s minimal essential medium (EMEM) (Sigma-Aldrich, Tokyo, Japan) supplemented with 10% (v/v) foetal bovine serum (FBS) (Funakoshi, Tokyo, Japan), 0.3% (w/v) tryptose phosphate broth (TPB) (Sigma-Aldrich), and 100 U/ml penicillin-streptomycin (Wako, Tokyo, Japan) at 37 °C in a humidified atmosphere containing 5% CO₂. Viruses were propagated in Vero cells cultured in EMEM with 2% FBS and 0.3% TPB at 37 °C. The titter of the PEDV NK94P6 and Fukuoka-1 Tr(−) strains were 2.8 × 10⁶ TCID₅₀/ml and 2 × 10⁴ TCID₅₀/ml, respectively.
Transmissible gastroenteritis coronavirus - TGEV (vaccine strain h-5; Nisseiken, Tokyo, Japan) was propagated in Vero cells; porcine reproductive and respiratory syndrome virus - PRRSV (live PRRS vaccine - Ingelvac PRRS® MLV- Boehringer Ingelheim company); Japanese Encephalitis virus – JEV and Getal virus - GV (live vaccine – Kyoto Biken company, Kyoto, Japan).

A full description of the crossbred vaccinated animals used in this study is by Sanglard et al. (2020) (link). Briefly, 906 F1 (Landrace × Large White) replacement gilts from 2 commercial farms in North Carolina were vaccinated (139 ± 17 d old) intramuscularly with a commercial modified life PRRSV vaccine (Ingelvac PRRS MLV, Boehringer Ingelheim Animal Health, Ames, IA). These animals were predominantly half-sibs of the Landrace purebred population described above. Blood samples were collected at ~50 d (52- and 53-d postvaccination for one farm, and 46 d postvaccination for the other farm) after vaccination in 3 contemporary groups (CG; days of blood collection). Samples were processed for measurement of S/P ratio against PRRSV using the same method as described for the purebreds. From now on, we will be referring to S/P ratio following PRRSV vaccination as S/P_Vx. Of these 901 gilts, 811 had farrowing performance recorded for up to 3 parities for litter size traits, including NBA, NSB, MUM, NBD, and TNB. There was no evidence of a PRRSV outbreak during this period. This dataset will hereinafter be referred to as P_{Cross_Vx} (performance in vaccinated crossbred sows). Summary statistics for the crossbred/PRRSV vaccination data are presented in Table 1.

Relatively clean piglets, free from PRRSV, CSFV, Pseudorabies virus (PRV), and Porcine circovirus2(PCV2) infections, as confirmed by serology tests and virus nucleic acid detection, were housed in a sterilized animal facility. The experimental and animal handling protocols were approved by the Ethics Committee on Experimental Animal Usage and Animal Welfare, Shenyang Agricultural University. A live attenuated PRRS vaccine (Ingelvac PRRS® MLV, batch number 245-f85b) was purchased from Boehringer Ingelheim Animal Health Co., Ltd. (USA). A CSF vaccine (live CSFV rabbit-source vaccine, batch number 20200916) was purchased from Shanghai Haili Biotechnology Co., Ltd. (Shanghai, China).

All animals in groups I, II and III (10 animals/group) were vaccinated on day 14 after weaning by intramuscular (i.m.) administration of a 2-ml dose of the commercial PRRSV-2 based Ingelvac® PRRS MLV (Boehringer-Ingelheim) into the neck muscle. Animals in group IV (control group, 8 animals) were mock-vaccinated with 0.9% NaCl on day 14.

The NADC30-like PRRSV (v2016/ZJ/09-03) strain, isolated at the Asian Veterinary Research and Development Center [Boehringer Ingelheim (China) Investment Co., Ltd.] was used as the challenge virus (26 (link), 28 (link)–30 (link)). Three PRRSV commercial vaccines were used in this study, including Ingelvac PRRS^® MLV (Boehringer Ingelheim), and another two domestic KV commercial vaccines.