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

• Published in: Journal of general virology Vol. 82; no. 1; pp. 129 - 138
• Main Authors: de Carvalho Nicacio, Cristina, Sallberg, Matti, Hultgren, Catharina, Lundkvist, Ake
• Format: Journal Article
• Language: English
• Published: England Soc General Microbiol 01.01.2001
• Subjects: Amino Acid Sequence; AN protein; Animals; Antibody Formation; Disease Models, Animal; Epitope Mapping; Epitopes - analysis; Hantavirus - genetics; Hantavirus - immunology; Hantavirus Infections - blood; Immunity, Cellular; Interferon-gamma - analysis; Interleukin-2 - analysis; Interleukin-4 - analysis; Interleukin-6 - analysis; Lymphocyte Activation; Medicin och hälsovetenskap; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Inbred CBA; Molecular Sequence Data; N protein; Nucleocapsid Proteins - genetics; Nucleocapsid Proteins - immunology; Puumala virus; Recombinant Proteins - immunology; T-Lymphocytes, Helper-Inducer - immunology
• ISSN: 0022-1317; 1465-2099
• DOI: 10.1099/0022-1317-82-1-129

Microbiology and Tumor Biology Center, Karolinska Institutet, S-171 77 Stockholm, Sweden 1 Division of Clinical Virology, F68, Oral Microbiology, F88, and Basic Oral Sciences, F59, Huddinge University Hospital, S-141 86 Huddinge, Sweden 2 Swedish Institute for Infectious Disease Control, S-171 82 Stockholm, Sweden 3 Author for correspondence: Cristina de Carvalho Nicacio. Fax +46 8 33 07 44. e-mail cristina.de.carvalho{at}mtc.ki.se 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.