Interestingly, several unknown genes have been found to be highly altered in expression levels in response to stress/pathogen induction. Clearly, the function of these unknown gene products needs to be further investigated. Although EST and microarray analysis are limited, as, for example, important immune mediators that do not alter significantly in transcript expression levels but are post-translationally modified or are involved in the early parts of
signal cascades and at low expression levels, these approaches cover most of the current knowledge of shrimp immunity while the whole genome analysis remains unavailable. However, to compliment these approaches, proteomic approaches are being employed as well as, but both are restricted by the absence of good transformation vectors and permanent cell lines, in contrast to insects, confining the subsequent analysis to the use of transient gene knockdown and heterologous gene expression studies and the use of yeast two-hybrid systems (see next section).