Relative expression of immune related genes in the seven-point time course of mammary lactation and involution. Immune-related transcripts that were differentially expressed in the seven-point lactation/involution time course were grouped into five categories representing different immunological functions. The number of transcripts in each category is shown in brackets. Genelists of all transcripts assigned to these immunological categories are available online. (a) For each category, the frequency of transcripts in each expression profile cluster was plotted. Statistically significant associations, as determined by Onto-Express, are indicated with asterisks. The Y axis indicates the percentage of each expression profile cluster, and the X axis indicates the expression profile cluster. (b) The mean combined expression profiles of transcripts in each immunological category are also shown (right). The Y axis indicates the mean normalized signal intensity, and the X axis indicates the seven developmental timepoints from lactation (L) and involution (I; see Fig. 2).