Rotavirus Double Infection Model to Study Preventive Dietary Interventions.

Rotaviruses are the main cause of acute diarrhea among young children worldwide with an increased frequency of reinfection. Several life style factors, such as dietary components, may influence such processes by affecting the outcome of the first rotavirus infection and therefore having a beneficial impact on the anti-rotavirus immune responses during any subsequent reinfections. The aim of this research was to develop a double-infection model in rat that mimics real-life clinical scenarios and would be useful in testing whether nutritional compounds can modulate the rotavirus-associated disease and immune response. Three experimental designs and a preventive dietary-like intervention were conducted in order to achieve a differential response in the double-infected animals compared to the single-infected ones and to study the potential action of a modulatory agent in early life. Diarrhea was only observed after the first infection, with a reduction of fecal pH and fever. After the second infection an increase in body temperature was also found. The immune response against the second infection was regulated by the preventive effect of the dietary-like intervention during the first infection in terms of specific antibodies and DTH. A rotavirus-double-infection rat model has been developed and is suitable for use in future preventive dietary intervention studies.

Supplementing suckling rats with whey protein concentrate modulates the immune response and ameliorates rat rotavirus-induced diarrhea.

Group A rotaviruses (RV) are the most common causative agents of acute gastroenteritis in children <2 y. The present study was designed to establish the effect of a bovine whey protein concentrate (WPC) in a RV infection model in suckling rats. From d 3 of life, suckling Lewis rats received daily supplements of WPC, WPC plus lactoferrin (LF), standard infant formula (SIF), or water (RV-infected group and an untreated, uninfected reference group). On d 8 of life, heterologous simian RV SA-11 was inoculated orally in the WPC-RV, WPC+LF-RV, SIF-RV, and RV groups. WPC and WPC+LF reduced diarrhea incidence from approximately 90% in RV group to approximately 60% in WPC-RV and WPC+LF-RV groups (P < 0.05), whereas the area under the curve (AUC) of severity along time diminished from approximately 10 AUC in the RV group to approximately 6 AUC in both supplemented groups (P < 0.05). Serum levels of anti-RV antibodies, splenocyte proliferation, and interferon-gamma secretion after specific stimulation were significantly lower in the WPC-RV and WPC+LF-RV groups than in the SIF-RV and RV groups. In the intraepithelial intestinal compartment, RV infection increased the proportion of typical mucosal T cells (IE-T CD8alphaalpha+); however, this modification was controlled by WPC and WPC+LF supplementation. In general, for most of the parameters studied, the SIF-RV and RV groups did not differ. In summary, daily supplementation with WPC or WPC+LF in early life considerably reduces the severity of RV-induced acute gastroenteritis and modulates the immune response against the pathogen.