Computer-aided Image Analysis Research Articles

Tumor angiogenesis as a prognostic factor in ovarian carcinoma

The growth of a malignant tumor requires the formation of new capillaries. Quantification of these microvessels is difficult. The purpose of this study was to establish an objective technique for quantifying angiogenesis and to evaluate whether microvessel quantity may predict tumor aggressiveness in patients with ovarian carcinoma. Endothelial area was used to quantify microvessel density in immunohistochemically stained sections of 28 International Federation of Gynecology and Obstetrics Stage IIIC ovarian carcinomas. The endothelial area was measured with a computer-aided image analysis system in the subepithelial stroma of highest vascularization. The endothelial area in the specimens of 14 patients who survived for > or =6 years was compared with that of 14 patients matched for stage and treatment who died of the disease. The mean tumor area analyzed was 5.04 +/- 0.23 mm2. The mean endothelial area per mm2 of stroma from survivors and dead patients was 0.038 +/- 0.026 mm2 and 0.110 +/- 0.034 mm2, respectively (P < 0.0001). No significant differences were found in histology, tumor grade, status of lymph nodes, and amount of residual tumor. Image analysis was used to overcome the potential subjectivity of manual counts. Computer-assisted image analysis can evaluate accurately the angiogenic potential in ovarian carcinomas. Tumor angiogenesis may prove to be a prognostic factor in patients with ovarian carcinoma. This study suggests that the measurement of the endothelial area would be clinically useful in determining microvessel density [See editorial on pages 2219-21, this issue.]

Tumor angiogenesis as a prognostic factor in ovarian carcinoma

BACKGROUND The growth of a malignant tumor requires the formation of new capillaries. Quantification of these microvessels is difficult. The purpose of this study was to establish an objective technique for quantifying angiogenesis and to evaluate whether microvessel quantity may predict tumor aggressiveness in patients with ovarian carcinoma. METHODS Endothelial area was used to quantify microvessel density in immunohistochemically stained sections of 28 International Federation of Gynecology and Obstetrics Stage IIIC ovarian carcinomas. The endothelial area was measured with a computer-aided image analysis system in the subepithelial stroma of highest vascularization. The endothelial area in the specimens of 14 patients who survived for ≥6 years was compared with that of 14 patients matched for stage and treatment who died of the disease. RESULTS The mean tumor area analyzed was 5.04 ± 0.23 mm2. The mean endothelial area per mm2 of stroma from survivors and dead patients was 0.038 ± 0.026 mm2 and 0.110 ± 0.034 mm2, respectively (P < 0.0001). No significant differences were found in histology, tumor grade, status of lymph nodes, and amount of residual tumor. CONCLUSIONS Image analysis was used to overcome the potential subjectivity of manual counts. Computer-assisted image analysis can evaluate accurately the angiogenic potential in ovarian carcinomas. Tumor angiogenesis may prove to be a prognostic factor in patients with ovarian carcinoma. This study suggests that the measurement of the endothelial area would be clinically useful in determining microvessel density [See editorial on pages 2219-21, this issue.] Cancer 1997; 80:2257-62. © 1997 American Cancer Society.

Sun Hats and Ichnofabrics: Fourth International Ichnofabric Workshop, San Salvador Island, Bahamas, March 15-22, 1997

Sun Hats and Ichnofabrics: Fourth International Ichnofabric Workshop, San Salvador Island, Bahamas, March 15-22, 1997

Effect of Multifunctional Additive on Filler Dispersion in Carbon-Black- and Silica-Filled Natural Rubber Compounds

The effect of multifunctional additive (MFA) on filler dispersion in carbon-black- (CB) and silica-filled natural rubber (NR) compounds has been studied. Silica dispersion, measured by computer-aided image analysis and scanning electron microscopy (SEM), showed a substantial improvement when MFA concentration is increased from 1 to 3 phr. After this level, there is a further but small improvement. However, for CB-filled NR compounds, CB dispersion showed a substantial improvement when the MFA used between 0 and 1 phr. As in silica-Filled NR compounds, there is only a small improvement in dispersion after 1 phr.

The initial reactions of graphite and gold with blood.

The initial reactions of graphite and gold with blood were investigated by short-time exposure to capillary blood and detection of surface-adsorbed plasma proteins and cells with an immunofluorescence technique. Antibodies specific to fibrinogen, complement factors C1q and C3c, prothrombin/thrombin, von Willebrand factor, and platelet- and leukocyte-membrane antigens were used. The fluorescence intensity was quantitated by computer-aided image analysis. Fibrinogen was the most abundant plasma protein immobilized on either surface, and dense populations of platelets adhered to the protein layer. Complement factors and prothrombin/thrombin were found on the graphite surface, localized in fibrin clots or related to platelets. Platelets were activated (expression of selectin CD62) on both surfaces but more extensively so on the gold surface. Activation of polymorphonuclear granulocytes (PMNGs), measured as expression of integrin CD11b, was seen on both surfaces but with different kinetics. On the graphite surface, the CD11b expression was only transient whereas on gold it increased with time. Our data indicate that graphite is more thrombogenic than gold but less inflammatory.

Reactions of two hydrophilic surfaces with detergents, protein and whole human blood

The surface chemistry of moscovite mica and hydrophilic glass was characterized by ESCA. The adsorption of detergents and lysozyme was measured by surface force methods, ellipsometry or ESCA. The results show that the protein has a higher affinity to the mica surface. A biological characterization of the surfaces was performed by exposure to whole blood, followed by detection of surface-adsorbed plasma proteins and cellular antigens by immunofluorescence. The brightness of the fluorescence was measured by computer-aided image analysis. The results show that hydrophilic glass was the most efficient activator of serine protease cascade enzymes. Platelets were activated at both surfaces, but were shown to leave the glass surface with time. The glass surface was more inflammatogenic than the mica surface as determined by the CD11b-integrin expression of PMN-cells. The results indicate that the nonself recognition of the surfaces is an array of subreactions, the kinetics of which determine the outcome of the blood-material contact.

Myofibroblasts and arteriolar sclerosis in human diabetic nephropathy

We examined the biopsy specimens of 62 patients with diabetic nephropathy to establish whether the myofibroblast (MF) has a role in progressive interstitial fibrosis and to ascertain whether a relationship existed between MF activity and severity of arteriolosclerosis. MF were identified by morphology and α smooth muscle actin (αSMA) immunostaining. Analysis of vascular injury was performed by counting the number of interstitial arterioles after staining endothelial cells with von Willebrand factor (VWF) antibody. Arteriosclerosis was quantified by using a computer-aided image analyzer to measure the arteriolar wall surface and total arteriolar surface area, and the ratio of wall to total surface area was expressed as the index of arteriosclerosis (IA). Fractional area of interstitium (IFA), αSMA, and collagen III (Coll III) were quantitated by point counting. Results were related to structural and functional parameters using rank correlation coefficients. There was a strong correlation between IFA and Coll III staining ( r = 0.83; P < 0.001). The αSMA staining correlated with IFA ( r = 0.56; P < 0.001) and Coll III ( r = 0.47; P < 0.001), and there were significant correlations between aSMA and total urinary protein ( r = 0.47; P < 0.001), renal function (plasma creatinine) at time of biopsy ( r = 0.51; P < 0.001), and the percent change in plasma creatinine after 4 years (ΔCr)( r = 0.37; P = 0.01). The IA correlated significantly with Coll III ( r = 0.29; P = 0.02), glomerular filtration rate (GFR) ( r = 0.39; P = 0.008), and creatinine ( r = 0.33; P = 0.01), but no correlation was observed between αSMA and IA ( r = 0.16; P = 0.23) or IA and ΔCr ( r = −0.04; P = 0.8). Strong correlations could be shown between arteriolar density, IFA ( r = 0.75; P < 0.001), αSMA ( r = −0.36; P = 0.034), and Coll III ( r = −0.66; P < 0.0001). The MF appears to have a significant role in the progression of diabetic nephropathy. Ischemia secondary to arteriosclerosis may contribute to interstitial fibrosis through fibroblast modulation into MF.

Experimental approach to a biological characterization of materials

Titanium oxide surfaces with thin (4 to 5 nm) or thick (30–40 nm) TiO2 layers and rough (Rrms 1.9 μm) or smooth (Rrms 0.45 μm) surface structure were exposed to capillary blood for 5 s through 64 min. The adsorption of main plasma proteins (albumin, IgG, fibrinogen), binding of cascade enzymes (serine proteases) and adhesion and activation of blood cells was measured with immunofluorescence techniques using specific antibodies, the binding of which was quantitated by computer-aided image analysis. The activation of cascade enzymes was detected with antibodies against prothrombin/thrombin (terminal step in the coagulation cascade), C1q and C3c (initial complement activation), terminal complement complex (TCC), and plasmin (terminal step in fibrinolysis). The activation of cells was measured by expression of selectin (platelet CD62), expression of integrins (neutrophil CD11b), or respiratory burst (NBT test) of peritoneal leucocytes adhering to the surfaces after in vivo exposure. The results show different profiles of protein adsorption at the four surfaces. Fibrinogen was the dominating protein on all surfaces, significant amounts of IgG was found on the rough surfaces only. Prothrombin/thrombin and C1q were found initially on the thick-rough surface only. No TCC or plasmin levels were detected during the exposure time studied. Platelets and neutrophils were activated to a significantly higher degree on rough surfaces than on smooth, and neutrophils more on the rough surface with a thin oxide layer than on the thick one. The ensemble of antigens and enzyme activity detected shows a fingerprint which is unique for each material investigated.

The initial reactions of TiO2 with blood

The natural titanium oxide (TiO2) layer of commercial sheet titanium was dissolved in hydrofluoric acid. A new oxide layer was grown by oxidation in nitric acid or by annealing at 700 degrees C in air. At this temperature, reaction with nitrogen is unlikely. The purity of the oxidized sheet-titanium surfaces was investigated by Auger spectroscopy. The composition of both surfaces was TiO2 with carbon impurities. The carbon content of the acid-oxidized titanium was 20 +/- 2%, and the carbon content of the heat-oxidized titanium was 14 +/- 2% The initial reactions of the TiO2 surfaces with blood were investigated by short-time exposure to capillary blood and by detection of surface-adsorbed plasma proteins and cells with immunofluorescence. Antibodies specific to fibrinogen, complement factor C1q, prothrombin/thrombin, and platelet membrane antigen were used, and the fluorescence was quantitated by computer-aided image analysis. The results show that serine proteases are the dominating proteins adsorbed onto annealed titanium (C1q = 67 +/- 4.6; pt/t = 97 +/- 0.2; fib = 47 +/- 0.2). The adsorption of serine proteases was lower and the amount of fibrinogen was higher on the acid-oxidized surface (C1q = 46.3 +/- 2.6; pt/t = 25 +/- 2.9; fib = 64 +/- 0.7). Platelets adhered and spread on the annealed titanium surface within 5 sec of blood-material contact. The number of adhering platelets was higher on the acid-oxidized surface.

Amyloid precursor proteins protect neurons of transgenic mice against acute and chronic excitotoxic injuries in vivo

The β-amyloid protein precursor (APP) is well conserved across different species and may fulfill important physiological functions within the CNS. While high-level neuronal expression of amyloidogenic forms of human APP results in β-amyloid production and neurodegeneration, lower levels of neuronal human APP expression in neurons of transgenic mice may primarily accentuate physiological functions of this molecule. To assess the neuroprotective potential of human APP in vivo, mice from seven distinct transgenic lines expressing different human APP isoforms from the neuron-specific enolase promoter were challenged with systemic kainate injections ( n=30) or transgene-mediated glial expression of gp120 ( n=32), an HIV-1 protein capable of inducing excitotoxic neuronal damage. To quantitate human APP-mediated neuroprotection, the area of neuropil occupied by presynaptic terminals and neuronal dendrites in the neocortex and hippocampus of each mouse was determined using laser scanning confocal microscopy of double-immunolabelled brain sections and computer-aided image analysis. Compared with gp120 singly transgenic controls, mice from three of three human APP751/gp120 bigenic lines expressing the 751 amino acid form of human APP at low levels showed significant protection against degeneration of presynaptic terminals; two of these lines also showed significantly less damage to neuronal dendrites. Two of three human APP695/gp120 bigenic lines expressing human APP695 at low levels were protected against presynaptic and dendritic damage, whereas one low expressor line and a human APP695/gp120 bigenic line expressing human APP695 at higher levels showed no significant protection. In the corresponding human APP singly transgenic lines, overexpressing only specific human APP isoforms, significant protection against kainate-induced degeneration of presynaptic terminals and neuronal dendrites was found in two of three human APP751 lines and not in any of the four human APP695 lines tested. These results indicate that human APP can protect neurons against chronic and acute excitotoxic insults in vivo and that human APP isoforms differ in their neuroprotective potential, at least with respect to specific forms of neural injury. It is therefore possible that impairments of neuroprotective human APP functions or aberrant shifts in human APP isoform ratios could contribute to neurodegeneration.

Adhesion and activation of platelets and polymorphonuclear granulocyte cells at TiO 2 surfaces

The initial reactions of two TiO 2 surfaces with blood were investigated by short-time exposure to capillary blood and analysis of surface-adsorbed plasma proteins and surface-adhering cells by using immunofluorescence techniques. Antibodies directed against platelet membrane antigen and P-selectin were used to visualize platelet adhesion and activation. Acridine orange and anti-CD 11b were used to detect adhesion and activation of polymorphonuclear granulocytes (PMNs). Antibodies against thrombospondin were used as markers for platelet α-granules. The fluorescence intensity was quantitated by computer-aided image analysis. Commercially pure, polished sheet titanium was oxidized in two different ways: (1) the natural oxide was dissolved with hydrofluoric acid and a new oxide layer was grown by oxidation in nitric acid, or (2) annealing was performed at 700°C in air. Auger electron spectroscopy and x-ray photoelectron spectroscopy showed that both surfaces had similar composition consisting of TiO 2 covered by a carbonaceous surface contamination layer. The thickness of the oxide layer was 4 nm on the acid-oxidized surface and 39 nm on the annealed surface. Optical profilometry and scanning electron microscopy showed that the acid-oxidized surface was rough and the annealed surface was smooth. The fibrinogen/prothrombin-thrombin ratio in the initial protein film differed between the surfaces. The number of adhering platelets was larger at the surface with a high surface concentration of adsorbed fibrinogen. Platelet activation (CD62) and priming of PMNs (CD 11b) were also significantly higher on the acid-oxidized surface. The results indicate that non-self recognition of biomaterials is an array of transient reactions comprising proteinmaterial, protein-cell, and cell-cell interactions.

Determining specific growth rates in different regions of Salmonella typhimurium colonies

Computer-aided image analysis (IA) techniques were used to determine specific growth rates (μ) in different regions of Salmonella typhimurium colonies grown on solid medium at 30°C. Captured transmission images were converted to optical density values, allowing calculation of μ. Data show that growth was exponential throughout the colony during the period studied (between 13 and 21 h after inoculation), but that μ varied from 0.69 to 0.37 h -1 at the periphery and centre, respectively. Results demonstrate regional variation in μ values within colonies, and support conceptual models of colony development. The technique described illustrates that kinetic growth data can be derived within bacterial colonies, and this may lead towards an improved understanding of the growth dynamics of these structures.

Restriction sites as identification tags for lymphocyte cDNAs.

A cDNA library was prepared from BW 5147 murine lymphoma cells in lambda ecc III phage and randomly partitioned into 291 sectors, each with 800-1000 recombinant phage plaques. One sector was chosen for further characterization in terms of sensitivity to restriction endonuclease cutting. Aliquots of DNA preparations from this sector were treated with XhoI, SmaI, NcoI, PvuII, PstI, HindIII, EcoRI, BamHI, and ApaLI before being used as templates in a cell-free expression system. The polypeptide products were separated by two-dimensional (2-D) gel electrophoresis and radiofluorographs of the gels were submitted to computer-aided image analysis. The matched patterns were inspected for the presence or absence of spots upon individual endonuclease treatments. Thereafter the results were integrated in a data matrix which served as a basis to construct "restriction tags" for all spots. These (restriction) tags are binary numbers termed "cut numbers" and are a representation of the set of recognition sequences which are (or are not) part of the coding sequence. From 493 sequences (visualized as 2-D gel spots), 12 were not cut by any of the nine enzymes, while 45 were cut by all of them. The percentages of sequences resistant to enzyme treatment ranged between 17% and 77% for NcoI and XhoI, respectively. The enzyme treatments led to the appearance of a certain portion of "new spots", probably products from truncated sequences. From 512 possible cut numbers, 136 were assigned to the 493 spots. Restriction tags are available to facilitate retrieval of cDNA clones from the (partitioned) cDNA library.

Phenytoin-induced cerebral thrombosis in rats: cerebral ultrastructure, water content and ischaemic volume in the acute phase.

A new rat model for multifocal cerebral thrombosis has recently been reported (Tani et al., 1994; 1995). Ultrastructural changes in the cerebral neocortex in the acute phase were investigated in order to characterize the early pathological events in this model. A bolus injection of alkaline phenytoin solution (pH 10.8) into one internal carotid artery in the rat caused severe endothelial injury accompanied by thrombosis in the cerebral vasculature within 5 minutes, and severe oedema of the ipsilateral hemisphere within an hour. Cerebral water content was measured by the simple dry-wet method, and cerebral surface area and the surface area and volume of the ischaemic zone were measured using computer-aided image analysis. Good correlations were demonstrated between cerebral water content and cerebral surface area, and between the surface area and volume of the ischaemic zone. We report here that quantitative evaluation of acute cerebral damage induced by phenytoin solution is possible with high reliability using simple image analysis.

Relations between microstructure and macroscopic properties in modified lead titanate piezoceramics

Abstract The electromechanical behaviour of calcium (PTC) and samarium (PTS) modified lead titanate ceramics is found to be highly dependent on the microstructure. To obtain the microstructure-properties relationships, a thorough and accurate microstructural characterization of ceramics has been carried out by a combination of microscopy with computer aided image analysis. The study reveals that the average grain size and the percentage of porosity are the main factors affecting the macroscopic properties. It is also found that, in order to obtain the correct microstructure-properties relationships, the knowledge of both the behaviour as a function of the poling field and the temperature is necessary.

Initial reactions of whole blood with hydrophilic and hydrophobic titanium surfaces

Commercial sheet titanium was annealed in air at 700–800°C. The hydrophilic, annealed sheets were immersed in sterile distilled water and stored until use. The hydrophilic titanium was made hydrophobic by ultrasonication in water-saturated 1-butanol (1:10) for 30 min, followed by rinsing in absolute ethanol and water. The titanium surfaces were exposed to capillary blood for 5 s. Immobilised plasma proteins and cells were detected with immunofluorescence by specific, fluorescein-labelled antibodies. Quantitation of labelled antigen was made with computer-aided image analysis. Two distinct patterns of blood reactions were seen. On the hydrophobic surface, signals from anti-fibrinogen antibodies were dominant and large amounts of adhering platelets were seen. On the hydrophilic surface, signals from antibodies against complement factor C1 and prothrombin/thrombin were dominant and only a few platelets were found adhering to the surface. The results are discussed in relation to similar findings on hydrophilic and hydrophobic quartz glass surfaces.

Effect of smoking cessation on cervical lesion size

Summary Background Cigarette smoking has been postulated as a cofactor in the aetiology of cervical cancer, but a causal role is difficult to establish because of potential confounding by sexual behaviour. We have investigated the effect of cessation or reduction in cigarette smoking on the course of minor-grade cervical lesions. Methods In this intervention study 82 women volunteers with minor-grade lesions on colposcopy (cervical intraepithelial neoplasia grade 1 or less) attempted to give up smoking for 6 months. Smoking histories were taken at 3-monthly clinic visits and verified by measurement of salivary cotinine concentrations. At each clinic visit, a photograph of the cervix was taken; the image was digitised and computer-aided image analysis was used to assess lesion size, by investigators unaware of smoking status. Findings Of the 82 women, 17 stopped smoking completely for at least 6 months and 11 others reduced their smoking consumption by more than 75%. Of these 28 women, 23 (82%) showed a reduction in lesion size of at least 20% or 4 mm2 compared with 13 (28%) of the 47 non-quitters (odds ratio 12·0 [95% Cl 3·9-32·7]). The remaining seven women had unconfirmed smoking histories. There was a significant correlation between the extent of smoking reduction and the change in lesion size (X 2 for trend=31·55, p<0·0001). Adjustment for social class, method of contraception, and stage of menstrual cycle did not affect the results. Interpretation Our findings support a link between smoking and cervical disease and suggest that smoking cessation could have a beneficial effect on early cervical abnormalities.

Morphological recognition of fungal spore germination by a computer-aided image analysis and its application to antifungal activity evaluation

An automatic image analysis system has been developed for measuring the germination characteristics of fungal spores and assessing the antifungal activity of antifungal agent against fungal spore germination in liquid medium. The system is composed of a multi-well culture chamber, automatic stage, microscopic observation system, image analyzing system, and computer program. An image of spores displayed on a TV monitor was converted to the binary brightness image by properly adjusting the threshold brightness level. The binary image was further analysed by using a curvature-based shape representation technique. Thus obtained profile of each spore was expressed by the combination of four line elements: line, convex, concave, and apical. From these morphological characteristics of spore, the germinated spores could be discriminated. This system was successfully applied to the assessment of antifungal activity of amphotericin B against fungi: Aspergillus fumigatus, Curvularia lunata, and Fusarium solani.

Changes in flagellar movement of rat spermatozoa along the length of the epididymis: manual and computer-aided image analysis.

The different patterns of motility of rat spermatozoa during epididymal transit were studied in vitro using high-speed videomicroscopy. The sperm images were analysed after manual tracing as well as with a computer imaging system. The present work is the first which reports both the swimming path of the sperm head and the characteristics of flagellation in this species. The hook-shaped head of the rat spermatozoa allowed us to demonstrate the two-dimensional (2D) swimming movement compared to the three-dimensional (3D) sperm motion which was mainly related to rotation of the head. Immotile spermatozoa entered the initial segment of the testis and showed rigid flagella. The potential for sperm motility occurred abruptly in the proximal caput region, and different patterns of flagellation were observed: vibrating, motile in place, motile with a static curvature of the midpiece resulting in a spinning motion or a circular path, and forward progressive movement with regular rotation of the head. The pattern of sperm movement became homogeneous in the distal cauda where the whole sperm population swam in a straight line. A static curvature appeared in the midpiece portion when the spermatozoa reached the proximal caput region. The formation of the static curvature was observed on both sides of the rat flagellum which were easily indicated by the head-shaped projection of the head and the axonemal side of the principal wave. As soon as they moved, the spermatozoa successively initiated principal (P) and reverse (R) waves, but the waves were visible only distal to the static curvature. The midpiece stiffness progressively decreased during the epididymal maturation; simultaneously the static curvature showed a larger radius and then disappeared. Consequently, the initiation of waves which was first seen in the distal part of the flagellum of immature cells occurred progressively near the junction with the head of maturing spermatozoa. These changes in sperm motion previously shown in rams and now in rats might be a general phenomenon in mammals. The high resolution of this computer imaging system applied tosperm motion showing a well-characterized "side of the flagellum" should allow sensitive detection of biochemical effects on flagellar beating.

Antibody‐targeted superantigen therapy induces tumor‐infiltrating lymphocytes, excessive cytokine production, and apoptosis in human colon carcinoma

Bacterial superantigens are the most potent known activators of human T lymphocytes. To engineer superantigens for immunotherapy of human colon carcinoma, the superantigen, staphylococcal enterotoxin A (SEA) was genetically fused to the Fab region of the colon carcinoma-reactive monoclonal antibody C242. In the present study the effector mechanisms involved in the anti-tumor response to C242 Fab-SEA were characterized. Immunohistochemistry and computer-aided image analysis were used in studies of cryopreserved tumor tissue to evaluate the phenotype of infiltrating cells and their cytokine profiles in response to therapy. Human T cells and monocytes were recruited to the tumor area and penetrated the entire tumor mass within hours after injection of C242 Fab-SEA. The production of cytokines at the single-cell level was found to be dominated by tumor necrosis factor (TNF)-alpha, interleukin (IL)-2, IL-4, IL-5, IL-10, IL-12, interferon (IFN)-gamma, granulocyte-macrophage colony-stimulating factor, and transforming growth factor-beta, whereas IL-1-alpha, IL-1ra, IL-1 beta, TNF-beta, IL-3, IL-6, and IL-8 were undetectable. Most of the TNF-alpha, IL-2, IL-12, and IFN-gamma were made by the infiltrating human leukocytes, while the colon carcinoma cells were induced to produce IL-4, IL-10, and TNF-alpha. Up-regulation of IFN-gamma receptors and TNF R p60 receptors was found, while the TNF R p80 receptor was absent. The cytokine production, T cell infiltration, and CD95 Fas receptor expression concomitantly occurred to induce programmed cell death in the tumor cells. This was followed by a strong reduction of the tumor mass that was seen within 24 h after C242 Fab-SEA infusion. These findings demonstrate that antibody-superantigen proteins efficiently recruit tumor-infiltrating lymphocytes actively producing a variety of cytokines likely to be essential for the therapeutic effects observed in the model. Although the humanized SCID model has obvious limitations in its predictive value for treatment of human cancer, we believe that these results encourage clinical evaluation of antibody-targeted superantigens.