Estudo imuno-histoquímico do carcinoma adenóide cístico de glândula salivar menor / Immunohistochemical study of minor salivary gland's adenoid cystic carcinoma

A expressäo de um painel de anticorpos, constituídos pelas citoqueratinas 7, 8, 10, 13, 14, 18 e 19, vimentina e HHF-35, foi estudada em 21 casos de carcinomas adenóide císticos de glândula salivar menor, de diferentes sub-tipos histológicos, utilizando-se a técnica da imunohistoquímica, pelo método da estreptpavidina-biotina. Os resultados mostraram que nos tumores cribriformes, as células luminas das estruturas ductais foram positivas para as citoqueratinas 7, 8, 14, 18 e 19 e negativas para a vimentina e HHF-35, enquanto as células externas dos ductos, as células que revestiam os espaços pseudo-císticos e as células periféricas dos cilindros foram negativas para as citoqueratinas testadas e positivas para a vimentina e HHF-35. Nos tumores tubulares, enquanto as células internas dos ductos mostraram-se positivas para as citoqueratinas 7, 8, 14, 18 e 19 e negativas para vimentina e HHF-35, as células periféricas das estruturas ductais, apresentaram-se sempre positivas para a vimentina e HHF-35 e ocasionalmente positivas para a citoqueratina 14. Nas neoplasias do subtipo sólido, observou-se positividade esporádica das células, especialmente para as citoqueratinas 7 e 14, bem como para a vimentina. Os nossos achados mostraram que o carcinoma adenóide cístico, de um modo geral, mimetiza, em seu perfil imuno-histoquímico, o segmento de ducto intercalado da glândula salivar normal, apresentando variaçöes que sugerem diferentes graus de diferenciaçäo para os seus três subtipos histológicos. Os tumores tubulares representam a variante mais diferenciada, os tumores sólidos, o subtipo menos diferenciado, e os tumores cribiformes, neoplasias de um grau intermediário de diferenciaçäo entre aquele visto nas outras duas variantes histológicas

Radioimmunotherapy of human hepatocellular carcinoma xenografts with 131I-labelled antiferritin antibody.

The effects of 131-labelled antiferritin polyclonal antibody for the treatment of established hepatocellular carcinoma (HC-04) in athymic nude mice were evaluated. 131I-labelled antiferritin antibody localised specifically to a subcutaneous tumour with a mean of 8.1% of the infused dose per gram of tumour at 24 h after infusion when the experiment was started 15 days after inoculation and with a mean of about 6.5% of the infused dose per gram of tumour when the experiment was started 30 days after tumour transplantation. The concentrations of 131I-antiferritin antibody in tumour delivered a mean of 1994 cGy to tumour following infusion of 500 microCi of radiolabelled antiferritin antibody in the early group and a mean of 1600 cGy in the late group. Treatment with 500 microCi led to regression of the tumour in 55% of animals in the early group and 44% in the late group. In contrast, unlabelled antiferritin and 131I-labelled IgG failed to exert any significant effect on tumour growth. The transplanted tumours in the early groups of animals had relatively higher concentration of ferritin than those in the late group. There was accelerated inhibition of tumour growth and prolonged survival in animals in the early group compared with those in the late group.

Reduction of immunogenicity by covalent modification of murine and rabbit immunoglobulins with oxidized dextrans of low molecular weight.

This communication describes the covalent modification of monoclonal and polyclonal antibodies with oxidized dextrans of low molecular weight to generate conjugates having low immunogenicity in vivo. Conjugation conditions were optimized to generate monomeric, dextran-modified antibodies, free of both high-molecular-weight polymeric aggregates and unmodified antibodies. Conjugates could be prepared with varying levels of dextran substitution. These conjugates retained optimal immunoreactivity as well as in vivo pharmacokinetics and tumor-localization properties. In addition, multiple i.v. administrations of dextran-modified antibodies in animals did not elicit a measurable immune response to either the antibody or the dextran portion of these conjugates.

Radioimmunoimaging of tumors with radioactive antibody against a glycoprotein (GP68) found in developing mouse brain.

The in vivo localization of a polyclonal antibody (pAb) against a glycoprotein with a molecular mass of 68 kDa (GP68), which was found in developing mouse brain, was studied in murine tumor models to evaluate potential applications of this antibody for in vivo radioimmunodetection and/or therapy of cancer. The tissue distribution of 125I-labeled GP68 pAb 3 days after i.v. injection into mice bearing four different kinds of solid tumor revealed a high uptake ratio by adenocarcinoma 755 and Lewis 3LL lung cancer. In contrast, the uptake ratio was low in mice bearing Ehrlich solid tumor and sarcoma-180 (S-180). These uptake ratios accorded well with the in vitro binding activity of this antibody with the tumor cells. In an immunoscintigraphic study, adenocarcinoma 755 was successfully visualized with 67Ga-labeled GP68 pAb. The results of these biodistribution and in vivo radioimmunoscintigraphic studies suggest that GP68 antibody may be applicable to the diagnosis and/or therapy of cancer.

Mammary tumor immunoscintigraphy in rats: the use of 131I-anti-estriol 3-sulfate antibody.

The scintigraphic imaging of mammary tumors with anti-estriol 3-sulfate (E3 3-S) antibody was studied in rats. A chemical carcinogen, 7,12-dimethylbenz(a)anthracine (DMBA), induced mammary tumors in Sprague-Dawley female rats. Highly specific anti-E3 3-S antibody was prepared and radioiodinated by [131I]NaI using the chloramine-T method. At 24 h after administration of 131I-anti-E3 3-S antibody, goat anti-guinea pig immunogloblin G (IgG) was injected as the second antibody (SA) and nuclear scintigraphy was performed. Mammary tumors were clearly visualized following SA injection.

Quantitation of antigen in tissue by immunofluorescence image analysis.

A method is described to measure antigen(s) in tissue section using an image analysis system to quantitate immunofluorescence following staining with fluorescein isothiocyanate (FITC)-conjugated antibody. The antigen utilized was an 125I-labeled goat anti-glomerular basement membrane antibody (1409 cpm/micrograms) administered intravenously to each of 11 Sprague-Dawley rats in doses ranging from 1.09 to 34.72 mg IgG. 24 h later, both kidneys were obtained for quantitative immunofluorescence following staining of tissue sections with FITC-labeled rabbit anti-goat IgG and for determination of radioactivity which reflects the amount of goat IgG present in isolated glomeruli. A linear correlation (r = 0.97) was observed between the dose of administered goat 125I-IgG and the amount bound to isolated glomeruli over the entire dosage range. A highly significant correlation (r = 0.98) was also seen between the mean brightness per glomerulus as determined by quantitative immunofluorescence and the amount of 125I-IgG bound per glomerulus but only at values less than 500 pg of IgG per glomerulus. Above these levels no correlation was observed, suggesting the presence of hidden epitopes in the bound goat IgG or the lack of availability of the FITC-labeled rabbit antibody.

Teratogenic antibody internalization by rat visceral yolk-sac endoderm in vitro: an ultrastructural colloidal gold tracer study.

Previous work from our laboratory has demonstrated that specific rabbit immunoglobulins G (IgG) against a glycoprotein antigen of rat kidney proximal tubule or a cross-reacting visceral yolk-sac endodermal cell antigen will induce abnormal embryonic development when they are injected into pregnant rats during the period of organogenesis. It has been proposed that these antibodies may induce embryopathy by interfering with functions of the visceral yolk-sac placenta, an important organ providing nutrients to the embryo at this stage of development. In order to gain some insight into the underlying pathogenic mechanism(s) in which specific teratogenic IgG may interfere with visceral yolk-sac functions, we examined the uptake of these teratogenic IgG by the visceral yolk-sac endodermal cells at the electron microscopic level. The results demonstrated that teratogenic rabbit IgG specifically localized on the fuzzy coat of the external apical cell membrane of the visceral yolk-sac endoderm at the intermicrovillous region. Within 5 min, the IgG were rapidly internalized via coated pits and micropinocytic vesicles. Within 30 min, an increasing proportion of gold particles appeared within uncoated vesicles or vacuoles of various sizes; most of the gold particles were in close proximity to the inner membranous lining of the vesicles. Similar findings were observed after 1- or 2-hr incubation. After 24- to 48-hr culture, however, the gold particles appeared to have dissociated from the inner surface of the vesicle membrane.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of injecting antibodies to mouse nerve growth factor into the chick embryo.

The function of NGF in chick embryos was studied by injecting antibodies to mouse nerve growth factor (NGF). The uptake of mammalian antibodies into the 8- to 15-day-old chick embryo was followed by an enzyme-linked immunoassay. Normal rabbit antibodies (250 micrograms) were administered to the yolk, of which less than 5% was found in the embryo (300 ng of IgG per g wet wt of embryo). The concentration was proportionally lower when 100 micrograms anti-NGF antibodies were injected (40 ng/g). The concentration of anti-NGF antibodies was 1.5 times higher following injection directly into the body of the embryos. The effects of injecting antibodies at days 3-7 were studied in 10-day-old embryos by measuring the diameter frequencies of neurons in sympathetic and sensory ganglia. In comparison with controls, significantly smaller neurons were found in the sympathetic ganglia in embryos directly injected with anti-NGF. In the spinal ganglia, distribution of neuron diameters did not differ between anti-NGF-treated embryos and controls. Finally, the ability of different antibodies to mouse NGF to inhibit the in vitro activity of recombinant chick NGF was investigated. Total block was found at 1000-2000 ng of IgG per ml for most of the antibodies tested, levels not reached when injecting the embryo with antibodies to NGF. We conclude that the main reason for the limited effects in chick embryos by injection of NGF antibodies is due to the low levels of penetration of the anti-NGF IgG into the embryo.

Radiation enhancement of radiolabelled antibody deposition in tumors.

Recent clinical observations led to the use of external radiation to increase tumor targeting by radiolabelled 131-I antiferritin. Examination of increased uptake of 131-I labelled antiferritin following external radiation was carried out in syngeneic implanted hepatomas (H4IIE, 3924A, 7800, and 7777). Exposure to 10 Gy increased the tumor: liver uptake ratio from 1.55 to 1.86 for H4IIE; from 1.56 to 2.0 for 7800; from 1.34 to 1.97 for 7777; and from 1.05 to 1.19 for 3924A. The pattern of uptake varied among the different tumor types, reflecting their inherent differences in vascularity, tumor permeability, antigen density and growth rate, all of which influence antibody targeting of the tumors. When tumor and liver were irradiated, the tumor showed increased differential uptake of labelled antibody compared to normal liver. 51-Cr labelled erythrocytes were used to study the relative vascularity and blood pooling in H4IIE hepatoma and normal tissue. External radiation to the tumor did not increase the uptake of 51-Cr labelled erythrocytes in any site. These studies provide an insight into the role of external radiation as a modality that increases radiolabelled antibody targeting in hepatoma.

In vivo administration of antibodies against type I collagen in rat: the specific accumulation in spleen.

[125I]-labelled rabbit antibodies against rat type I collagen and non-immune IgG were injected into rat circulation. The kinetics of their clearance and the biodistribution in different organs were studied. Both preparations showed very similar clearance rate, the kinetics fitting bi-exponential approximation with characteristic parameters t1,1/2 = 201 +/- 20 min before 320 min and t2,1/2 = 1350 +/- 450 min at times over 320 min for antibodies and 258 +/- 45 min and 890 +/- 140 min for IgG. The specific affinity of the circulating antibodies did not decrease within 24 hours. The antibodies were specifically accumulated in spleen, where their accumulation was 5-fold higher than that of non-immune IgG. Accumulation of antibodies was maximal 3 hours after the injection. The localization ratio (i.e. the ratio of the amount of the antibodies per g of tissue to that per g of blood) reached a maximum 24 hours after the injection and remained stable for 120 hours. Immunofluorescent staining of spleen sections resulted in a bright fluorescence of dense collagenous structures in the trabeculae and in the wall of the central follicular arterium, bright spot fluorescence in the marginal zone of the follicle, and diffuse fluorescence in the red pulp. These findings suggest an unusually high accessibility of collagen type I in spleen to circulating blood plasma components.