Lymphoid andnon-lymphoid cells inthe epithelium andlamina propria ofintestinal mucosa ofpigs

Thejejunumandileumof5dayoldand adultnormalpigsandof45dayoldgerm freepigswereusedtostudythelymphocytepoolsintheepithelium andlamina propriaby sequential treatments with EDTA,fourhours, and12hoursofcollagenasetreatment. Inadultanimalsthe incubation ofthejejunal wallwithEDTA resulted inmean (SD)26-8(10.9) X106 intraepithelial lymphocytes per g of tissue. Theileal wallgavelowercell yields. Aftercomplete digestion ofthelamina propriaby collagenase a further yield of 35-2(10.2)X106/g lymphocytes was achieved. Theseparation ofthegutwall from5dayoldpigsresulted ina 10-fold lowertotallymphocyte yield, and the tissuewas totally digested afterfour hoursofcollagenase treatment. Many eosinophils andmastcells werefoundin thesuspensions fromadult animaltissues after thecollagenase treatment; 4-7X106/g and48X106/g, respectively. Thesuspensions after 12hourcollagenase incubation contained upto30%plasmacells. Almost allcells isolated byEDTA incubation were CD8+T cells. Aftercollagenase incubationCD4+andCD8+T lymphocytes were foundinallanimalgroups, andinadult animals upto20%surface Ig+cells were harvested. Whentheincorporation ofthe thymidine analogue bromodesoxyuridine wasusedtostudy thelymphocyte productioninvivo3 to7% lymphocytes inthe epithelium werelabelled 24hourslater (laminapropriaT lymphocytes about 1%).Inthisstudylymphoid aswellas non-lymphoid cells havebeenanalysed in mucosalcellsuspensions. The absolute cellyield pergramofmucosaltissue isa basis toestimate thepoolsizes ofintraepithelial andlaminapropria lymphocytes. (Gut1994; 35:1582-1589)