Contribution of antibody-secreting cells induced in mucosal lymphoid tissues of pigs inoculated with respiratory or enteric strains of coronavirus to immunity against enteric coronavirus challenge.

Abstract

Two antigenically related porcine coronaviruses, transmissible gastroenteritis virus (TGEV) which infects primarily the intestinal tract and causes severe diarrhea, and porcine respiratory coronavirus (PRCV) which infects the respiratory tract and causes subclinical or mild respiratory infections, presented a unique opportunity to study the interrelationship of gut-(GALT) and bronchus-associated lymphoid tissues (BALT) and their contribution to protective immunity against TGEV infection. Pigs were inoculated oral-nasally with TGEV or with PRCV at eleven days of age and challenged 24 days later with TGEV. All pigs initially given TGEV developed diarrhea and were completely protected against disease upon challenge. In contrast, pigs given PRCV had no clinical disease and shed virus in nasal secretions only; after challenge, 5 of 12 pigs developed diarrhea. Virus-specific IgG and IgA Ab-secreting cells (ASC) were enumerated by ELISPOT in the mesenteric and bronchial lymph nodes, spleens, and gut lamina propria at challenge and various post challenge days. Before challenge, in pigs exposed to TGEV, IgA-ASC in the duodenum and jejunum constituted the major ASC response. Conversely, PRCV-exposed pigs had mainly IgG-ASC in bronchial lymph nodes, with low ASC responses in the gut. After challenge, numbers of IgG-ASC increased rapidly in the gut lamina propria and mesenteric lymph nodes of only PRCV-primed pigs. Our results suggest that virus-specific IgG-ASC precursors derived in BALT of PRCV-primed pigs may migrate to the gut in response to TGEV challenge and contribute to the partial protection observed. The presence of IgA-ASC in the gut lamina propria of TGEV-primed pigs at the time of challenge correlated with complete protection against TGEV challenge. Thus a dichotomy exists in the BALT and GALT ASC responses; immunization via BALT induced a systemic type of response (IgG-ASC) and provided imperfect protection against an enteric pathogen, whereas immunization via GALT induced IgA-ASC and provided complete protection.

Role of FcγRIII in the nasal cavity of BALB/c mice in the primary amebic meningoencephalitis protection model

“…Studies have revealed that once the plasmablast leave the lymphoid nodes, they reach the lamina propria of the different mucosal membrane, where they differentiate into plasmatic cells due stimulation of IL-5 and IL-6 secreted by Th2 cells (Strober W, 2005). In addition, memory cells B and specific IgG antibodies have been proposed to accumulate in the lamina propria from inductor sites, and this same accumulation plays an important role in the protection against pathogens (VanCott et al 1994).…”

Maternal immunization and vitamin A sufficiency impact sow primary adaptive immunity and passive protection to nursing piglets against porcine epidemic diarrhea virus infection

“…The Vero cells infected with PEDV and mock antigens were grown and fixed in 96-well plates as described previously for TGEV ASCs ( 26 , 42 , 43 ). The ELISPOT assay for the quantification of PEDV-specific ASCs was performed following previous protocols ( 23 , 37 , 38 ).…”

Inmunidad inducida por las variantes virulenta y atenuada de la cepa CV-777 del virus de la diarrea epidémica porcina

“…El aislamiento y purificación de las CMN se realizó siguiendo procedimientos previamente descritos por otros autores (31,142,146,154). Se siguieron protocolos diferentes para el procesado de las muestras de intestino (duodeno e íleon), para el bazo y los ganglios linfáticos mesentéricos y para la sangre.…”

“…Nuestros resultados coinciden con trabajos realizados para otros virus gastroentéricos, en los que se ha comprobado que con la utilización de cepas de virus adaptadas al cultivo celular y administradas por vía oral u oronasal, se consigue un cierto grado de protección frente al virus virulento, aunque siempre menor que el descrito cuando los animales eran inoculados inicialmente con ese virus (17,115,117,119,142,154).…”

“…Frente al VGET se han utilizado, con resultados similares a los obtenidos por nosotros, cepas atenuadas tanto del mismo virus como de su variante respiratoria, el coronavirus respiratorio porcino (17,142). Con las cepas atenuadas de rotavirus, sin embargo, el grado de protección encontrado fue inferior al obtenido por nosotros para el VDEP (153,154,120).…”