T-helper and humoral responses to Puumala hantavirus nucleocapsid protein: identification of T-helper epitopes in a mouse model

Abstract

Puumala hantavirus (PUUV) is a rodent-borne agent causing nephropathia epidemica in humans, a milder form of haemorrhagic fever with renal syndrome occurring in Fennoscandia, central Europe and western Russia. In this study we characterized the immunogenicity of an E. coli-expressed nucleocapsid (N) protein of PUUV (strain Kazan-E6) in inbred mice (BALB/c, CBA and C57/BL6). The recombinant N (rN) protein raised PUUV-specific antibodies in all three tested murine haplotypes, and all IgG subclasses were detected. Epitope mapping using peptides spanning the N protein revealed that the B-cell recognition sites were mainly located at the amino-terminal part of the protein. Proliferative T-helper (Th) lymphocyte responses were detected in all haplotypes after a single immunization with rN. Several Th-recognition sites, spanning amino acids 6-27, 96-117, 211-232 and 256-277, were identified using overlapping peptides. Peptides representing the identified sites could also prime Th-lymphocytes to proliferate in response to recall with rN protein, thereby confirming the authenticity of the identified sites. The rN-primed Th-lymphocytes produced predominantly interleukin (IL)-2 and gamma interferon, together with lower levels of IL-4 and IL-6, indicating a mixed Th1/Th2 response.

Regulatory T cell-like responses in deer mice persistently infected with Sin Nombre virus

“…In this manner, it is evident that antigenic peptides can dictate the quality of an immune response by virtue of their affinity for MHC molecules (52). Supporting this contention, de Carvalho Nicacio et al found MHC-specific differences in proliferation magnitude to recombinant Puumala virus N-Ag in inbred strains of laboratory house mice (48). In addition, some viral peptides are antagonistic to T cell responses, such that they can impact effector T cell maturation (53)(54)(55).…”

“…The polyclonal T cell lines from acutely infected deer mice produced both type 1 and type 2 cytokines, including IFN-␥, IL-4, and IL-5, likely reflecting a polyclonal response and paralleling that of studies of house mice immunized with recombinant Puumala virus N-Ag (48). Absent in the response were the type 1 cytokines TNF and LT, suggesting that these cytokines have no or limited roles during deer mouse CD4 ϩ T cell responses to SNV.…”

“…The SNV N-Ag is capable of inducing vigorous T cell proliferation in immunized BALB/c mice (47), as does N-Ag from Puumala virus (48), and in deer mice immunized with a DNA vaccine encoding the N-Ag (31). It is possible that during the coadaptation of hantaviruses to their rodent reservoirs, natural selection favored rodents able to produce viral polypeptides that limited T cell signaling through the T cell receptor.…”

Hantavirus Infection

“…The severity of disease generally correlates with the number of CTL (10,37,51). CTL epitopes were identified in all three viral structural proteins, whereas NP again seems to be the predominant immunogenic protein (62,63).…”

Susceptibilidad genética a hantavirus Andes: Asociación entre la expresión clínica de la infección y alelos del sistema HLA en pacientes chilenos

“…Por otra parte, en un modelo murino en el que se administra la proteína N recombinante (Nr) del virus Puumala (PUUV, variedad de hantavirus de Europa), se encontró que el nivel de la respuesta humoral y celular estaba influenciada por el genotipo de los roedores, indicando que el haplotipo del huésped juega un papel importante en la respuesta inmune contra la proteína N de PUUV 25 .…”