So, in English, what are FHA and pertractin?
post #21 of 42
11/15/08 at 4:31pm
they are pieces of Pertussis.
Pertractin is the "house" or outer membrane protein that sticks to epithelial cells. FHA is the tendril that grabs on. "it is a fimbrial-like structure on the bacterial surface, and cell-bound pertussis toxin (PTx). Short range effects of soluble toxins play a role as well in invasion during the colonization stage."
http://www.textbookofbacteriology.net/pertussis.html for FHA Pertractin, just google for a refrence
|Characterization of Bactericidal Immune Responses following Vaccination with Acellular Pertussis Vaccines in Adults|
|Similarly, opsonization with the postimmunization sera failed to enhance attachment or phagocytosis of bacteria by neutrophils, and one postimmunization sample with a strong response to filamentous hemagglutinin caused an inhibition of phagocytosis that was statistically significant compared to that observed for the no-serum control. In summary, booster immunization of adults with acellular pertussis vaccines was not found to increase bactericidal activity over preimmunization levels. Identifying ways to promote bactericidal immune responses might improve the efficacy of acellular pertussis vaccines.|
|Neutralizing Antibodies to Adenylate Cyclase Toxin Promote Phagocytosis of Bordetella pertussis by Human Neutrophils|
I think most of us can agree here that the pertussis vax does not prevent transmission.
However doesn't it prevent some transmission? If you have pertussis but no symptoms you're much less likely to spread germs. You're not coughing all over the place, nose running, etc.
|Of particular interest is the lack of a significant ACT antibody response in children for whom the DTP or DTaP vaccines failed. This induced tolerance is intriguing and may be due to the phenomenon called “original antigenic sin” . In this phenomenon, a child responds at initial exposure to all presented epitopes of the infecting agent or vaccine. With repeated exposure when older, the child responds preferentially to those epitopes shared with the original infecting agent or vaccine and can be expected to have responses to new epitopes of the infecting agent that are less marked than normal. Because both vaccines contained multiple antigens (i.e., PT, FHA, PRN, and fimbriae), the patients who had been vaccinated responded to the antigens that they had been primed with and did not respond to the new antigen (i.e., ACT) associated with infection.|
|one postimmunization sample with a strong response to filamentous hemagglutinin caused an inhibition of phagocytosis that was statistically significant compared to that observed for the no-serum control|
PLUS, immunity is wearing off, most adults no long have immunity, and adults tend not to have the classic "whoop", so they are ill with pertussis without knowing it and spreading it around.
It's a very frustrating vaccine...
So what do we know about what the 2mo, 4mo, 6mo, etc series does for/to infants? Is the anti-toxin part that's supposed to make the really heavy coughing actually helping to some extent?
And are there any benefits to teen/adult vaccination? It seems like it's a rare adult who gets the really heavy, debilitating cough. Not impossible, but most cases seem like normal coughs (no one thinks whooping cough, I mean).
What's the most interesting thing you've learned? I have to ask this--I don't know enough to ask the question that would naturally lead here, so I'll just jump to the end-point.