I briefly mentioned Regulatory T cells today as a relatively newly discovered (or rediscovered depending on your viewpoint) part of our immune system. These are also known as suppressive T cells, but the cool kids just call them Tregs. (Like T. rex.....)
Here are a couple of recent papers that will give you an entry into the literature in this field.
The Journal Immunology had a series of review articles in 2007 to mark their 50th anniversary. One of these was entitled:
Special regulatory T cell review: The suppression problem!
The concept of T-cell mediated suppression evolved more than 30 years ago. At that time it spawned many claims that have not stood the test of time. The rediscovery of suppression phenomena and regulatory T cells over the past 15 years created schizophrenic responses amongst immunologists. Some claimed that the new proponents of suppression were, once again, bringing immunology into disrepute, whilst others have embraced the field with great enthusiasm and novel approaches to clarification. Without faithful repetition of the "old" experiments, it is difficult to establish what was right and what was wrong. Nevertheless, immunologists must now accept that a good number of the old claims were overstated, and reflected poor scientific discipline.
Tregs and allergic disease
Allergic diseases such as asthma, rhinitis, and eczema are increasing in prevalence and affect up to 15% of populations in Westernized countries.
In summary, current evidence suggests that human CD4+CD25+ T cells and IL-10–producing Tregs have the capacity to suppress Th2 responses to allergen and that this process may be defective in those who develop allergic sensitization.