T cell requirement differs for initial development of TEC H/P (A) vs. induction
of TEC H/P by splenocytes or transferred T cells (B, C). A, Naïve
IFN-γ−/−CD28−/−
NOD.H-2h4 males, 5–6 wk old, were given NaI water. One wk later, groups
of mice were given rat IgG (Iso), anti-CD4 (GK1.5), anti-CD8 (116–13.1)
or both antibodies every 10–12 days (see Methods). Thyroids were removed
after 8 wk on NaI water (15 wk of age). Anti-CD4 or anti-CD8 alone had little
effect on TEC H/P severity in most mice (p >0.1). Depletion of both
CD4+ and CD8+ T cells significantly
inhibited TEC H/P development (p < 0.0001). N=8 (Iso), 7 (anti-CD8),
9 (anti-CD4) and 9 (anti-CD4 + 8). B, splenocytes from
IFN-γ−/−CD28−/−I
females with severe TEC H/P were cultured and transferred to female SCID
recipients (see Methods). Recipients were given NaI water and thyroids were
removed 28 or 60 days later as indicated. Groups of recipients were given rat
IgG (Con), anti-CD4 or anti-CD4 and anti-CD8 beginning 6 or 30 days after cell
transfer as indicated. Antibody injections were repeated at 12–14 day
intervals. Thyroids were removed from all treated mice at day 60. Mice given
anti-CD4 or anti-CD4 and anti-CD8 at day 6 (before recipients had severe
disease) developed minimal TEC H/P at day 60 (p < 0.001), whereas delaying T
cell depletion until day 30 when recipients had severe TEC H/P had no effect (p
> 0.1). N= 9 (Con, Day 30); 10 (Con, Day 60); 5 (anti-CD4 day 6); 9
(anti-CD4 and 8, day 6,) C, 5 (anti-CD4 and 8 day 30). D, Splenocytes from
IFN-γ−/−
CD28−/− females were cultured 72 hr. Cells were
separated into CD4+ or CD8+ subsets as
described in Methods, and transferred to SCID females. Recipients were given NaI
water and thyroids were removed 28 days later. Splenocytes and
CD4+T cells, but not CD8+, T cells
induced severe TEC H/P in recipient mice. N= 8 (spl); 12
(CD4+); 11 (CD8+) and 8 (CD4 and CD8).
Results are representative of two (C) or three (A, B) separate experiments.
Thyroids and spleens of recipients of CD4+ T cells had no
detectable CD8+ T cells (not shown).