jinku gismu

x1 is a vaccine/immune-system stimulant protecting x2 against disease x3 introduced by method x4.

Also serum; inoculation (= jestu'u veljinku). See also jurme, mikce, jesni, bilma.

In notes:

t1=j1 is an immune-system deficiency of j2.
x1 is an ismu of x2, having the same meaning, but with all places except the x3-th (li/set) zi'o-deleted.