R e v is ta d a S o c ie d a d e B r a s ile ir a d e M e d ic in a T r o p ic a l 2 1 (1 ): 4 1 -4 2 , J a n - M a r , 1 9 8 8
N O T A P R É V IA
T R Y P A N O S O M A C R U Z I A N T I G E N S D E T E C T E D B Y I M M U N O E L E C T R O N
M I C R O S C O P Y I N T H E S P L E E N O F M I C E S E R O L O G I C A L L Y P O S I T I V E B U T P A R A S I T O L O G I C A L L Y C U R E D B Y C H E M O T H E R A P Y .
(P r e lim in a r y R e p o r t).
S.G. Andrade, L.A.R. Freitas, S. Peyrol, A.R. Pimentel and M. Sadigursky.
A n “ immunological m em ory” has been claim ed as responsible for the persistence of serological positive tests in patients with C hagas’ disease after being subjected to specific treatm ent and apparently cured. In mice, negative parasitological tests m ay coexist with positive specific indirect immunofluorescence test (IIF T ) after prolonged treatm ent with Nifurtimox or B enznidazole1. W ith the objective of investigating w hether a lack of correlation between parasitological cure and negative serology is due to the presence of T.
c r u z i antigens bound to the dendritic splenic cells, the p resent investigation was perform ed to identify, by im m unoelectron m icroscopy, the presence o f T. c r u z i antigens specifically labeled with peroxidase. W ith this purpose, mice infected with T. c r u z i (5 x 104 blood forms) of the 12 SF strain, both in the acute and in the chronic phase o f the infection, were subjected to treat m ent with Benznidazole (lOOmg k/bw ) during 90 days. Parasitological and serological tests were per form ed 3 to 6 months after the end of treatm ent. The parasitological tests consisted of haem oculture, xeno- diagnosis and subinoculation of the blood into suckling mice. A s serological tests the specific indirect immu- nofluorecence reaction using culture forms as anti gens, was used. Investigation of specific antigens in the spleen: sections of the spleen were fixed in paraform al dehyde for im m unoelectron microscopy; cryostat sec- tios (6 to 8/xm) were treated with monospecific purified rabbit anti-71 c r u z i antibodies and revealed with goat anti-rabbit im munoglobulin bound to peroxidase. A s control, sections not treated with the specific anti-se- rum were used. T he labeled tissues were included into E pon resin blocks; ultrathin sections were examined without contrast with a Zeiss E M 109 electron mi croscope. The following experim ental groups were subm itted to im munolabeling with peroxidase: I - 10 m ice treated and parasitologically negative; II - 8 mice treated and parasitologically positive; III - 5 untreated infected c introls; IV - 2 positive controls (acute phase o f infectio.:); V - 5 intact controls. Results: in the acu tely infected mice (positive controls), amastigotes
S u p p o r te d b y th e U N D P / W O R L D B A N K / W H O S p e c ia l P r o g r a m a n d C o n s e lh o N a c io n a i d e D e s e n v o lv im e n t o C ie n tif ic o e T e c n o ló g ic o - C N P q .
R e c e b id o p a r a p u b lic a ç ã o e m 9 / 9 / 8 7 .
forms of T. c r u z i (Figure 1) showed positive im muno labeling with peroxidase on the parasite surface mem brane, in the intracellular vacuole m em brane and in desintegrated fragments inside macrophages. T he spe cificity of the reaction was controled by the exam ina tion of sections w ithout the specific antibodies, which were negative. In the untreated controls as well as in the treated mice (parasitologically positives or negati ves) serologically positives by IIF T , it was detected in the germinal centre of folicles of the spleen the presen ce o f positive specific deposits on the m em brane of the dendritic cells cytoplasm ic processes (Figures 2,3).
N o t a P r é v ia . A n d r a d e S G , F r e ir a s L A R , P e y r o l S , P im e n te l A R , S a d i g u r s k y M . T r y p a n o so m a cru zi a n ti g e n s d e t e c t e d b y im m u n o e l e c t r o n m i c r o s c o p y in t h e s p l e e n o f m i c e s e r o l o g i c a l l y p o s i t i v e b u t p a r a s i t o l o g i c a l l y c u r e d b y c h e m o t h e r a p y ( P r e l i m i n a r y R e p o r t ) . R e v i s t a d a S o c i e d a d e B r a s i le i r a d e M e d i c i n a T r o p ic a l 2 1 : 4 1 - 4 2 , J a n - M a r , 1 9 8 8
C o n c lu s io n : It was demonstrated the presence of specific antigens of T . c r u z i in treated and parasitolo gically cured mice, w hich could be correlated with the presence o f an “ immunological mem ory” resisting post-treatm ent. These results showed the viability o f the m ethod for identifications o f T. c r u z i antigen parti cles in the tissues and open new perspectives for the in terpretation of therapeutic results in C hagas’ disease.
R E F E R E N C E S
1. A n d r a d e S G , M a g a lh ã e s J B , P o n t e s A L . E v a lu a t io n o f C h e m o th e r a p y w ith B e n z n id a z o le a n d N ifu r t im o x in m ic e in f e c te d w ith T r y p a n o s o m a c r u z i str a in s o f d iff e r e n t t y p e s . B u lle tin o f th e W o r ld H e a lt h O r g a n iz a tio n 6 3 : 7 2 1 - 7 2 6 , 1 9 8 5 .
