MEDICINE UPDATE: DIAGNOSTICS AND TREATMENTS 3. Results
Comparable results were obtained for several mea- sures of cellular immunity. In particular, antigen- specific CD4 and CD8 cellular expression of the cytokines interferon- and interleukin-4 were evident at specified time points for several vaccine antigens.
4. Discussion
The data presented in this report demonstrate that young foals are capable of immune activation after a three-dose immunization series with a multivalent vaccine, despite the presence of maternal antibodies.
Although immune activation does not automatically translate into protection, several of the immune in- dicators measured showed comparable expression in foals vaccinated at 3 months of age, relative to those in the control group of foals initially vaccinated at 6 months of age. In a high-risk situation in which immune activation may be required earlier than at the completion of a conventional vaccine series, our data support that foals can respond to immunization that is initiated at 3 months of age in a manner comparable to that in foals initiated at an older age, provided that the immunization protocols include three doses followed by a booster at 11 months of age.
