HUMORAL IMMUNE RESPONSE AGAINST RNA VIRUSES.
Phone: +46 8 728 63 22 / 6320 / 6327
Fax: + 46 8 33 13 99
Group leader: Ewa Björling, PhD (e-mail)
Research associate: Åke Lundkvist, PhD (e-mail)
Post-doc fellows:
Alexander Plyusnin, PhD (e-mail)
Diana Koletzki, PhD (e-mail)
PhD students:
Cristina de Carvalho Nicacio (e-mail)
Andreas Mörner (e-mail)
Pia Skott (e-mail)
Technician:
HUMORAL IMMUNE RESPONSE AGAINST RNA VIRUSES.
Research profile:
To contribute to the understanding of the mucosal and systemic humoral immune
response against different RNA viruses; hantavirus, human immunodeficiency
virus (HIV) and measles.
HANTAVIRUS
Hantaviruses, belonging to the family Bunyaviridae, cause two distinct,
severe human infections; haemorrhagic fever with renal syndrome (HFRS) and
hantavirus pulmonary syndrome (HPS). HFRS is characterized by fever, renal
dysfunction and hemostatic imbalance. Approximately 200,000 cases are reported
annually worldwide. Four HFRS-associated hantaviruses have been described.
Hantaan (HTN) virus causes severe HFRS in Asia. Seoul (SEO) virus, reported
to cause moderately severe HFRS, is linked to urban rats and therefore potentially
found all over the world. Dobrava (DOB) virus, which was isolated on the Balkan
peninsula, has been found to be an important cause of the more severe type
of HFRS in this region. Puumala (PUU) virus, the cause of a milder form of
the disease, (nephropathia epidemica; NE), is found in Scandinavia, western
Russia, the Balkan region and in several central European countries. The mortality
of infections caused by HTN and DOB viruses are reported to be 3-12%. For
SEO viruses this figure is substantially lower (~ 1%) whereas for PUU virus
infection it is less than 0.2%.
HPS, a recently discovered disease entity in the Americas, involves adult
respiratory distress syndrome with a high mortality rate (~ 50%) and is caused
by Sin Nombre virus and related agents. No vaccine or acute therapy are available
against any hantavirus.
Our work is focused on the characterization of the humoral and cellular immune responses against hantavirus infections, pathogenesis, molecular epidemiology of European hantaviruses, and vaccine development.
HUMAN IMMUNODEFICIENCY VIRUS
HIV-1 and HIV-2 have both been discovered as causative agents of AIDS, and
considerable knowledge about their molecular characteristics, mechanisms of
gene expression and genomic complexity has been unraveled since then.
HIV-1, is today worldwide spread, and HIV-2 infection has today been documented
in Africa, Europe, The Americas and Asia, but is still mostly confined to
West Africa and Portugal.
HIV-2 infections, like HIV-1 infections, results in the production of neutralizing
antibodies predominantly directed against regions in the envelope glycoprotein,
and there is also in vitro evidence of cross-neutralizing antibodies
(for review see Kent and Björling 1997).
Many isolates of both HIV-1 and HIV-2 have been characterized by nucleotide
sequencing and from these studies we have learned that genetic variation is
a hallmark of these viruses, and that a consequence hereof is alterations
in both structure, function and immunogenicity within a single individual
throughout the lifelong infection with HIV.
Our HIV studies include identification of antibodies and presence of virus
in the oral and vaginal mucosa and also innate defense mechanisms in these
compartments and their interaction with HIV, and thereby contribute to the
understanding of the mucosal immune response of HIV.
The other aspect of this project is to further clarify the neutralization
mechanisms at the molecular level, and the development of a combinatorial
library from an HIV-2 immune donor in parallel with further studies with specific
peptides will clarify which part of the HIV-2 glycoproteins are the targets
for neutralizing antibodies. These reagents will then be used in therapeutic
and immunoprophylactic studies of general humoral immunity.
Recently, we have also started to investigate the usage of chemokine receptors
as cofactors for HIV-2 entry into target cells.
MEASLES
Measles, a viral infectious disease of childhood, is the most contagious infection
of man. The infection induces lifelong immunity but also an extended immune
suppression after recovery that is associated with increased susceptibility
to other infections, and in rare instances, persistent infection of the nervous
system. The immunization programs world-wide now prevent over 1.5 million
deaths from measles. However, measles and its complications are still responsible
for more than one million child deaths in developing countries each year,
which is more than all other childhood vaccine preventable diseases combined
are responsible for. This highlights the need to re-examine current tools
and strategies and to further increase the knowledge base that will enhance
the effectiveness of measles control efforts.
Our study is focused on contribution to the understanding of the mucosal and
systemic immune protection against measles virus and also further clarify
which parts that should be included in a future subunit long-lasting vaccine
to measles that can escape maternal antibodies. By the establishment of a
recombinant expression system for measles proteins suitable for in vitro
and in vivo studies of antigen specific immune responses, our
attempt is to use these recombinant proteins for characterization of the maternally
derived immunity in infants before measles vaccination, and furthermore use
these proteins for panning of an antibody library to derive clonal human neutralizing
Fabs specific for the N and H proteins. The biological characterization of
the anti-measles IgA specific response and the detection of antigenic sites
important for binding of IgA antibodies will elucidate the role of the mucosal
immune response against measles.
Selected publications:
-Hyperimmune sera against synthetic peptides representing the glycoprotein of human immunodeficiency virus type 2 can mediate neutralization and antibody dependent cytotoxic activity. Björling, E., Broliden, K., Bernardi, D., Utter, G., Thorstensson, R., Chiodi, F. and Norrby, E. Proc. Natl. Acad. Sci USA 1991. 88; 6082-6086.
-Identification of a unique antigenic site in the HIV endonuclease protein. Björling, E., Utter, G., Stålhandske, P., Norrby, E. and Chiodi, F. Journal of Virology 1991. 65; 4543-4546.
-Barbas, C., Björling, E., Chiodi, F., Dunlop, N., Cababas, D., Jones, T., Zebedee, S., Persson, M., Nara, P., Norrby, E. and Burton, D. Recombinant human FAb fragments neutralize human type 1 immunodeficiency virus in vitro. Proc. Natl. Acad. Sci. USA 1992, 89; 9339-9343.
-Autologous neutralizing antibodies prevail in HIV-2 but not in HIV-1 infection. Björling, E., Scarlatti,G.,vonGegerfelt, A., Albert, J., Biberfeld,G.,Chiodi, F., Norrby, E. and Fenyö, E-M. Virology 1993, 193: 528-530.
-Two V3 associated important neutralizing domains in the envelope glycoprotein gp 125 of human immnuodeficiency virus type 2. E. Björling, F. Chiodi, G. Utter, and E. Norrby. J of Immunology 1994; 152: 1952-1959.
-Protection of macaques against HIV-2 with a HIV-2 iscom vaccine. Putkonen, P., Björling, E., Åkerblom, L., Thorstensson, R., Lövgren, K., Benthin, L., Chiodi, F., Biberfeld, G., Morein, B., Norrby, E. and Wigzell, H. J Aquir Imm Defic Syndr 1994; 7:551-559.
-B-cell epitopes in the envelope glycoproteins of HIV-2 and SIV. Kent, K., and Björling, E. 1996. HIV Molecular Immunology Database 1996, by Korber, B.T.M., Walker, B.D., Moore, J.P., and Myers, G. Los Alamos National Laboratory, Los Alamos, New Mexico.
-B cell sites in the HIV glycoproteins. Ewa Björling and Erling Norrby. 1996. Book chapter in; Immunology of HIV infection, by S. Gupta, Plenum press.
- Lundkvist Å, Hörling J, Athlin L, Rosén A, Niklasson B. Neutralizing human monoclonal antibodies against Puumala virus, causative agent of nephropathia epidemica: a novel method using antigen-coated magnetic beads for specific B cell isolation. J Gen Virol 1993;74:1303-1310.
-Hörling J, Cheng Y, Plyusnin A, Persson K, Lehväslaiho H, Vaheri A, Niklasson B, Lundkvist Å. Nucleotide and deduced amino acid sequences of the M and S genome segments of a Swedish Puumala virus isolate. Virus Res 1995;39:321-330
-Hörling J, Lundkvist Å. Single aminoacid substitutions in Puumala virus envelope glycoproteins G1 and G2 eliminate important neutralization epitopes. Virus Research 1997;48:89-100.
-Heiskanen T, Lundkvist Å, Vaheri A, Lankinen H. Phage-displayed peptide targeting on Puumala virus neutralization site. J Virol 1997;71:3879-3885.41.
-Lundkvist Å, Cheng Y, Brus Sjölander K, Niklasson B, Vaheri A, Plyusnin A. (1997) Cell culture adaptation of Puumala hantavirus changes the infectivity for its natural reservoir, Clethrionomys glareolus, and leads to accumulation of mutants with altered genomic RNA S segment. J Virology 71: 9515-9523
-Ulrich R, Lundkvist Å, Meisel H, Koletzki D, Sjölander Brus K, Gelderblom H R, Borisova G, Schnitzler P, Darai G, Kruger D H. (1998) Chimeric HBV core particles carrying a defined segment of Puumala hantavirus nucleocapsid protein evoke protective immunity in an animal model. Vaccine 16: 272-280. 42.
-Salonen E-M, Parren PWHI, Graus YF, Lundkvist Å, Fisicaro P, Vapalahti O, Kallio-Kokko H, Vaheri A, Burton DR. (1998) Human recombinant Puumala virus antibodies: cross-reaction with other hantaviruses and use in diagnostics. J Gen Virol 79:659-665.
-Lundkvist Å, Wiger D, Hörling J, Brus Sjölander K, Plyusnina A, Mehl R, Vaheri A, Plyusnin A. Characterization of Puumala hantavirus from Norway. J Gen Virol, in press
