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ludc webb

Harry Björkbacka

Researcher

ludc webb

Lack of Ability to Present Antigens on Major Histocompatibility Complex Class II Molecules Aggravates Atherosclerosis in ApoE-/- Mice

Author

  • Maria Wigren
  • Sara Rattik
  • Ingrid Yao Mattisson
  • Lukas Tomas
  • Caitriona Grönberg
  • Ingrid Söderberg
  • Ragnar Alm
  • Lena Sundius
  • Irena Ljungcrantz
  • Harry Björkbacka
  • Gunilla Nordin Fredrikson
  • Jan Nilsson

Summary, in English

BACKGROUND: Hypercholesterolemic mice lacking factors required for activation of CD4+ T cells are characterized by reduced development of atherosclerosis. Consequently, it has been assumed that atherosclerosis involves loss of tolerance against modified self-antigens generated in response to hypercholesterolemia and that presentation of such antigens on major histocompatibility complex class II (MHCII) leads to activation of proatherogenic Th1 cells. In this study, we wanted to determine the role of antigen presentation on MHCII in atherosclerosis development.

METHODS: Apolipoprotein E (ApoE-/-) mice deficient for MHCII (ApoE-/-MHCII-/-) were used to study the role of MHCII in atherosclerosis development.

RESULTS: Compared with ApoE-/- mice, ApoE-/-MHCII-/- mice had reduced levels of CD4+ T cells, immunoglobulin G and M levels, and Th1 and Th2 cytokines in plasma. CD8+ T cells were increased and regulatory T cells were reduced both in spleen and in lesions of ApoE-/-MHCII-/- mice. Decreased plasma levels of inflammatory cytokines in ApoE-/-MHCII-/- mice indicated reduced systemic inflammation. Despite this, ApoE-/-MHCII-/- mice had significantly more atherosclerosis as assessed by en face Oil Red O staining of the aorta (4.7±2.9% versus 1.9±1.3%; P<0.01) and cross-sectional area of subvalvular lesions (7.7±2.2×105 µm2 versus 4.6±2.8×105 µm2; P<0.05). Cell transfer and blocking antibody studies suggested that loss of regulatory T cells is the most important cause of aggravated atherosclerosis in ApoE-/-MHCII-/- mice.

CONCLUSIONS: Our observations demonstrate that antigen presentation on MHCII has important protective functions in atherosclerosis and that this is primarily the result of activation of regulatory T cells. These findings have implications for understanding the possible risks and benefits of immunosuppressive therapy in patients with cardiovascular disease.

Department/s

  • Cardiovascular Research - Immunity and Atherosclerosis
  • EpiHealth: Epidemiology for Health
  • EXODIAB: Excellence in Diabetes Research in Sweden
  • Cardiovascular Research - Cellular Metabolism and Inflammation

Publishing year

2019-05-28

Language

English

Pages

2554-2566

Publication/Series

Circulation

Volume

139

Issue

22

Document type

Journal article

Publisher

Lippincott Williams & Wilkins

Topic

  • Cardiac and Cardiovascular Systems

Status

Published

Research group

  • Cardiovascular Research - Immunity and Atherosclerosis
  • Cardiovascular Research - Cellular Metabolism and Inflammation

ISBN/ISSN/Other

  • ISSN: 1524-4539