R e v ista d a S o c ie d a d e B ra s ile ir a d e M e d ic in a T ro p ic a l 2 2 (3 ): 1 6 1 -1 6 2 , J u l-S e t, 1 9 8 9
C A R T A A O E D IT O R
M O R P H O M E T R IC S T U D Y O F
H E P A T IC G R A N U L O M A IN
O F F S P R IN G O F
S c h is t o s o m a m a n s o n i
IN F E C T E D M IC E
T h e re is a considerable interval betw een th e exposure to antigens and the first ap p earan ce o f specific antibodies in m am m als, at birth. T his interval is occup ied b y the transm ission o f m atern al antibodies. Specifically in m ice, little antibod y is tran sferred b y the yolk sac an d placen ta, the passive tran sm issio n is alm ost ex clusively p o stn atal b y m ean s o f abso rption of lacteal secretion in the intestine. In the pro xim al sm all intestine, th ere is a selective absorption o f Ig G , w hich is b ound to a n in testinal F c fragm ent recepto r, interna lized b y endo cyto sis an d th en ab so rb ed b y the v ascu lar system . In the distal sm all intestin e little selectiv ity is found. A t d a y 16 after birth the transm ission o f Ig G ceases, the recep tors d isap p ea r from th e gut, although
sy stem an d the hepatic g ranu lom ato us lesions w ere studied in o rd e r to evaluate the effects o f m atern al tran sm ission o f sch istoso m al antig ens an d antibod ies to offspring o f S c h i s t o s o m a m a n s o n i in fected m ice in relation w ith the tim e o f m o th er infection.
C 5 7 B L /6 fem ale m ice 8 -1 0 w eeks old w ere in fected su b cu tan eo u sly ( 10 ± 5 cercariae p er m ouse) and then challenged five tim es each tw o weeks**. Infecte d fem ales w ere sep arated in tw o groups o f ten. In the first group, the fem ales w ere m a te d ten d ay s following the th ird inocula tion, breeding a t the 6 0 th d a y after the first inoculation. T h e second group w as m ated the d ay after th e la s t in ocula tion, breedin g a t the 8 0 th day after the first inoculation. T h e m ice b o m o f the first group fo rm ed the exp erim ental group A an d the m ice b o m o f the second fo rm ed the experim ental group B. T h e control group w as fo rm ed b y m ice b o m o f non-in fected fem ales. O ffspring o f in fected a n d non- infected fem ales w ere in fected a t 0 -4 d a y s b y placing each one in a P e tri dish, contain in g 2 0 ± 2 cercariae/5
the m aternal m ilk still contain s im m unoglobulins2 . O thers studies suggest sen sitization to schistoso m al antigens b y m ean s o f the tran sfer o f circulating an tigens from m o th er to foetus th rough p lacen ta o r m ilk^ 1.
W e have carried o u t som e experim ents in w hich ad u lt w orm s w ere reco v ered b y perfusion o f the po rtal
R esearc h sup ported by C N P q .
A dd ress: Dr? Silvia M L M onte negro , D e p arta m e n to de Im un ologia, C en tro de P esq u isas Aggeu M a g a lh ã e s /F IO C R U Z - C aix a Po stal: 74 72 - 5 0 7 3 0 R ecife-P E , Brasil.
R e c e b id o p a ra p u b lic a ç ã o em 9 /5 /8 9 .
m l o f aq u ariu m w ater a t 3 7 ° C fo r 3 0 m in utes6 . T h e cercariae w ere co u n ted in a P e tri d ish b efore an d after infection. T h e litters w ere killed at the 5 0 th d ay o f infection an d ad u lt w orm s w ere recovered b y perfusion o f the p o rtal sy stem . T h e livers w ere fixed in 10% form alin a n d paraffin sections w ere stain ed w ith hem ato xylin-eosin . T he g ranulo m atous lesions w ere m easu red b y a m orphologic p ro g ram video-plan (a system o f im age analysis m an ag ed b y a com puter). O n ly new ly fo rm ed granu lom atous lesio ns were m ea sured, e.g. cellular lesio n contain ing an eosinophilic m iracidium 1 4 . S tu d en t te st w as u se d to evaluate the differences.
C arta ao E ditor. M ontenegro S M L , A b a th FGC , C arvalho GL, C arvalho A B . M orphom etrie stu d y o f hepatic g ra n u lo m a in offspring o / S c h i s t o s o m a m a n so n i infected in mice. R evista da Socied a d e B rasileira de M ed icin a T ropical 2 2 :1 6 1 -1 6 2 , Ju l-Set, 1989
All groups had an efficiency of infection close to
95%. The maternal transfer of antibodies (and anti
gens) did not contribute to change susceptibility to
infection since the worm recovery was not significantly
different (p > 0 ,0 5 ) in experimental and control groups
(Table 1). Differences concerning area, perimeter and
mean diameter of granulomas were not significant
when groups A and B were compared, despite the
difference relative to the time of mother infection. Gra
nulomas of group A were smaller in comparison to that
of control group (p < 0,05). This finding could be
explained by exposure of the foetus to parasite anti
gens, resulting in reduced immunoresponsiveness and
pathology-5. Although immunotolerance response on
tissues in usually characterized by little or no cellular
reaction around eggs in the liver, this was not observed
in the present study. Further experiments are being
carried out to clarify some of the discussed results.
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