Streptococci

Moving Closer to a Strep Vaccine

In Antibodies, Emerging Markets, News by Vaccine Nation (Cameron Bisset)2 Comments

Researchers from the University of California have identified a possible solution to the often damaging immune response casued by strep for future strep vaccine

Researchers from the University of California have identified a possible solution to the often damaging immune response casued by strep for future strep vaccine

Group A Streptococcus (strep) is estimated to cost the US $2 billion annually thanks to lost time and productivity amongst its work force.   Whilst for most, the only symptom of strep will be a painful throat infection, for some the effects of strep can go further.

In some cases, the immune response caused by the presence of strep can cross-react with a patient’s heart valve tissue. this can cause rheumatic fever and damage to the heart. This problem has stood in the way of development for a strep vaccine for many years.

But researchers at the University of California, San Diego School of Medicine, have uncovered the building blocks of strep’s cell wall.

The cell wall of strwep is composed mainly group A carbohydrate (GAC), which is itself built from the bacterial sugar rhamnose and the human like sugar N-acetylglucoseamine (GlcNAc). It is believed that GlcNAc is responsible for the creation of antibodies capable of damaging the heart. The researchers suggest that preventing GlcNAc from adding to GAC could well form the basis of a safe vaccine for strep.

After further research, it was discovered that mutant strep strains lacking GlcNAc, whilst behaving in exactly the same mannor as strep, could be easily killed by human white blood cells.

The researcher will being to test the antibodies that successfully responded to the mutant strep strain against other strep candidates in non-human primates later this year.

Find the paper in Cell Host and Microbe here.

Comments

  1. redman2

    Your interpretation/comments on this data are not quite accurate. The autoimmunity seen in rheumatic heart disease that is caused by group A strep has nothing to do the carbohydrates that are discussed in this paper. In fact the auto-antibodies induced by strep infection are a result of molecular mimicry between the strep M protein and smooth muscle myosin. Protective immunity for GAS is M protein specific and that is the real barrier to the development of an effective vaccine, since there are over 100 M protein ‘types’. Please see Guilherme et al 2006 Molecular Mimicry in the autoimmune pathogensis of rheumatic heart disease. Autoimmunity V39:31-39 for a nice description. In point of fact both autoreactive T cells and antibodies have been shown. It is indeed possible to ‘edit’ and M protein antigen and create a protective vaccine that does not induce autoimmunity, and this has been through ph 2 clinical studies and been shown to induce opsonic antibodies (kills bacteria) and to not induce autoimmune responses. See this patent “Multivalent streptococcal vaccine compositions and methods for use
    WO 2003065973 A3″ and this publication Safety and Immunogenicity of 26-Valent Group A Streptococcus Vaccine in Healthy Adult Volunteers McNeil et al Clin Infect Dis. (2005) 41 (8): 1114-1122.

    1. Author
      cameron

      Hi Redman,

      thanks for the information! I shall dig out your recommended reading and have a look.

      Regards,
      Cam

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