Abstract P2-03-02: Detection of insulin receptor isoforms by mass spectrometry in breast cancer

Breast cancer cells express Type 1 Insulin-like Growth Factor Receptor (IGF1R) and Insulin Receptor (IR). These receptors have a role in breast cancer biology and mediate metabolism, proliferation, survival, and motility. IR gene undergoes differential splicing that generates two IR isoforms, IRA (exclusion of exon 11) and IRB. High levels of IRA expression in prenatal growth and development are observed, whereas IRB expression is more highly expressed in adult insulin responsive tissues. IRA overexpression is the predominant receptor isoform expressed in breast cancer specimens obtained from patients with endocrine resistant disease. To measure levels of IRA and IRB mRNA expression, we utilized IR isoform specific primers in quantitative reverse transcription PCR (qRT-PCR). The validation of IRA and IRB primers was determined via using IRA and IRB overexpressing clones of MCF7 cells. IRA and IRB mRNA expression was also studied in human adipose and liver tissues that majorly express the adult IRB isoform. Over 40 breast cancer cell lines and 20 ER+ patient tumor samples were studied to determine IRA and IRB mRNA expression. Total IR, IGF1R, IRS1, and IRS2 were also analyzed in cell lines and patient samples. Across the ATCC breast cancer cell lines and ER+ patient tumors, heterogeneity was found among all targeted genes. Using MCF-7 cells as control, we found one of the breast cancer cell lines, Du4475, has very high IRA mRNA expression level (200-fold of that in MCF-7). Using mass spectrometry technology, we quantified levels of IR isoform expression in Du4475 cells. Briefly, IR immunoprecipitates were subjected to SDS-PAGE gels and the IRA protein gel band was submitted for mass spectrometry. Since IRA does not contain exon 11, the identified unique peptide consistent with its expression is TFEDYLHNVVFVPRPS. After this IRA specific peptide was determined, the heavy-labeled (C13- and N15-containing) IRA peptide was used as an internal injection control to quantify the IRA level. Quantitative results of IRA peptode sequence were proportional to the mRNA levels previously detected in Du4475 cell lysate. Using MCF-7 IRB overexpression cell line MCF7L-IRB-C5, we identified two IRB peptides, KTSSGTGAEDPRPSR and TSSGTGAEDPRPSR at exon 11 region by mass spectrometry. Cell membrane and total cell lysates could also be used to detect IR protein isoforms by mass spectrometry analysis. Further measurement of IRA and IRB level on other breast cancer cell lines is ongoing. In summary, we are the first to use mass spectrometry to validate protein expression of IR isoforms at levels that correlate with mRNA expression. IRA mRNA and protein expression levels in breast cancer cell lines may serve as biomarkers to screen patients for targeted therapy.

Citation Format: Xihong Zhang, LeeAnn Higgins, Todd Markowski, Tzu-Yi Yang, Jacob Wragge, Kevin Murray, Bruce Witthuhn, Albert Barrios, Douglas Yee. Detection of insulin receptor isoforms by mass spectrometry in breast cancer [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P2-03-02.

Sepsis Code: dodging mortality in a tertiary hospital

Introducción

En el hospital de La Princesa comienza el “Código Sepsis” (CSP) en el año 2015, como un grupo multidisciplinar que dota al personal sanitario de herramientas clínicas, analíticas y organizativas, con el objetivo de la detección y el tratamiento precoz del paciente con sepsis. El objetivo de este estudio es evaluar el impacto de la implantación de CSP en la mortalidad y determinar las variables asociadas con un aumento de la misma.

Material y métodos

Se realizó un estudio analítico retrospectivo de los pacientes con activación de la alerta CSP de 2015 a 2018. Se recogieron variables clínico-epidemiológicas, parámetros analíticos y factores de gravedad como el ingreso en Unidades de Cuidados Críticos (UCC) y la necesidad de aminas. La significación estadística se estableció en una p < 0,05.

Resultados

Se incluyeron 1.121 pacientes. La estancia media fue de 16 días y un 32% requirieron ingreso en UCC. La mortalidad mostró una tendencia lineal descendente estadísticamente significativa del 24% en 2015 hasta el 15% en 2018. Las variables predictivas de mortalidad con asociación estadísticamente significativa fueron el lactato > 2 mmol/L, la creatinina > 1,6 mg/dL y la necesidad de aminas.

Conclusiones

La implementación de Código Sepsis disminuye la mortalidad de los pacientes con sepsis y shock séptico. La presencia de una cifra de lactato > 2 mmol/L, los niveles de creatinina > 1,6 mg/dL y/o la necesidad de administrar aminas en las primeras 24 horas, se asocian con un aumento de la mortalidad en el paciente con sepsis.

DUSP9-mediated reduction of pERK1/2 supports cancer stem cell-like traits and promotes triple negative breast cancer

Breast cancer remains a complex disease resulting in high mortality in women. A subset of cancer stem cell (CSC)-like cells expressing aldehyde dehydrogenase 1 (ALDH1) and SOX2/OCT4 are implicated in aggressive biology of specific subtypes of breast cancer. Targeting these populations in breast tumors remain challenging. We examined xenografts from three poorly studied triple negative (TN) breast cancer cells (MDA-MB-468, HCC70 and HCC1806) as well as HMLE^HRASV12 for stem cell (SC)-specific proteins, proliferation pathways and dual-specific phosphatases (DUSPs) by quantitative real-time PCR (qRT-PCR), immunoblot analysis and immunohistochemistry. We found that pERK1/2 remained suppressed in TN xenografts examined at various stages of growth, while the levels of pp38 MAPK and pAKT was upregulated. We found that DUSP was involved in the suppression of pERK1/2, which was MEK1/2 independent. Our in vitro assays, using HMLE^HRASV12 xenografts as a positive control, confirmed increased phosphatase activity that specifically influenced pERK1/2 but not pp38MAPK or pJNK levels. Family members of DUSPs examined, showed increase in DUSP9 expression in TN xenografts. Increased DUSP9 expression in xenografts was consistently associated with upregulation of SC-specific proteins, ALDH1 and SOX2/OCT4. HRAS driven HMLE^HRASV12 xenografts as well as mammospheres from TN breast cancer cells showed inverse relationship between pERK1/2 and increased expression of DUSP9 and CSC traits. In addition, treatment in vitro, with MEK1/2 inhibitor, PD 98059, reduced pERK1/2 levels and increased DUSP9 and SC-specific proteins. Depletion of subsets of SOX2/OCT4 by fluorescence-activated cell sorting (FACS), as well as pharmacological and genetic reduction of DUSP9 levels influenced ALDH1 and SOX2/OCT4 expression and reduced mammosphere growth in vitro as well as tumor growth in vivo. Collectively our data support the possibility that DUSP9 contributed to stem cell-like cells that could influence TN breast tumor growth. Conclusion: Our study shows that subsets of TN breast cancers with MEK1/2 independent reduced pERK1/2 levels will respond less to MEK1/2 inhibitors, thereby questioning their therapeutic efficacy. Our study also demonstrates context-dependent DUSP9-mediated reduced pERK1/2 levels could influence stem cell-like traits in TN breast tumors. Therefore, targeting DUSP9 could be an attractive target for improved clinical outcome in a subset of basal-like breast cancers.

1095 Effective image-guided medical management in effusive constrictive pericarditis

A 59 year old man was admited to hospitalization for persistent chest pain related to acute pericarditis. Within the admision tests, a transthoracic echography was performed, showing a moderate pericardial effusion with ventricular septal bounce and significant respiratory variations in mitral and tricuspid inflows, all of it consistent with effusive-constrictive pericarditis (Panel A). Anti-inflammatory treatment with ibuprofen and colchicine was started.

During the first 48 hours of admission there was a clinical and hemodinamic worsening in the patient’s condition that forced the performance of a pericardial window, obtaining a very little quantity of dense pericardial fluid. Looking for a more accurate study of the pericardium, a cardiovascular magnetic resonance (CMR) was performed, revealing a thick heterogeneous pericardial effusion (Panel B) and a significant late gadolinium enhancement of both pericardial layers (Panel C). All these findings where consistent with an effusive constrictive pericarditis with persistent inflammatory activity despite high doses of conventional inflammatory treatment. Furthermore, the growth of Propionibacterium acnes in the pericardial fluid disclosed the etiology of this condition.

Medical treatment was enhanced with high doses of intravenous corticosteroid, ceftriaxone and doxycycline. During the following days, the patient showed an excellent response achieving the complete clinical and echocardiographic relief of constrictive signs (Panel D).

Effusive constrictive pericarditis is characterized by the presence of pericardial effusion and constriction secondary to an inflammatory process of the pericardium. Pericardiectomy might be necessary in case of failure of medical treatment, a very common scenario in this kind of .pericarditis.

Our case is remarkable because it demonstrates the value of CMR to detect persistent inflammation of pericardium despite high doses of conventional medical treatment for pericaricarditis guiding the successful escalation to intravenous corticosteroid and avoiding the risk of an unnecessary cardiac surgery.

Abstract 1095 Figure.

Extraperitoneal laparoscopic ventral hernia repair: one step beyond

PURPOSE

The objective of the study was to analyze the experience of the Department of Surgery of two institutions of high complexity in Colombia, with the extra peritoneal ventral hernia repair by laparoscopy during the last 2 years and characterize the clinical and surgical aspects most relevant in the procedures performed.

METHODS

Observational, descriptive, retrospective study, case series type: collection of data by clinical history and analysis thereof including calculation of frequency and central tendency measurements.

RESULTS

59 Cases of Ventral Hernia Repair by laparoscopy, 41 with Transabdominal Preperitoneal approach and 18 totally Extraperitoneal. In total, 7 complications were presented as follows: 1 Case of recurrence, 1 case of chronic pain, 2 complications Dindo-Clavien IIIa and 1 complication IIIb.

CONCLUSIONS

The repair of the ventral hernia by Extraperitoneal route is an innovative approach of increasing popularity, which avoids the contact of the mesh with the intestines, thus avoiding the potential complications that this situation generates with good outcomes and at a lower cost.

Atypical presentation in adults in the largest community outbreak of leishmaniasis in Europe (Fuenlabrada, Spain)

Since 2009, the largest reported outbreak of leishmaniasis by Leishmania infantum in Europe was reported in Fuenlabrada, Spain. In our hospital, 90 adults with localized leishmanial lymphadenopathy (LLL) or visceral leishmaniasis (VL) were treated during this outbreak; 72% were men, and the mean age was 46.2 years (range 15-95 years). A total of 17 cases (19%) were LLL, an atypical form with isolated lymphadenopathies without other symptoms. All LLL cases occurred in immunocompetent subjects, and only one subject (6%) was a native of sub-Saharan Africa. Diagnosis was performed by fine needle aspiration cytology of the lymphadenopathy. Serology was negative in 38%. LLL outcomes at 6 months were benign, even with doses of liposomal amphotericin B that were often lower (10 mg/kg) than those recommended for VL in Mediterranean areas. A total of 73 subjects (81%) presented with typical VL; 66% of this group were immunocompetent, and 50% of those who were immunocompetent were descendants of natives of sub-Saharan Africa. The rK39 test and polymerase chain reaction were the most useful tests for confirmation of the diagnosis. An initial response to treatment was observed in 99% of cases, and relapses occurred in 14% of cases. Leishmaniasis should be included in the differential diagnosis of isolated lymphadenopathies in endemic areas. LLL could be considered a more benign entity, one different than VL, and less aggressive management should be studied in future investigations.

A New Formulation for Quenching Processes under Restricted Geometry Conditions in the Slow Exchange Limit

A quantitative treatment of quenching processes under restricted geometry conditions in the Slow Exchange Limit is presented. The expressions for KSV have been obtained for this limit in some common situations that can arise in studies under restricted geometry conditions, such as an inhomogeneous quencher distribution in the solution, the presence of oxygen in solution, or the case of solutions containing a mixture of receptors. These situations have been considered and incorporated into the treatment.

Levobupivacaine plus fentanyl versus racemic bupivacaine plus fentanyl in epidural anaesthesia for lower limb surgery

BACKGROUND

To compare the anaesthetic epidural effects of levobupivacaine plus fentanyl versus bupivacaine plus fentanyl in patients undergoing lower limb surgery.

METHODS

A single blind, randomised, prospective, multicentre study was designed to compare both therapies. The study was conducted in 10 tertiary hospitals. A total of 96 patients who were ASA I or II, who required at least a 24-hour-stay in the hospital and who were subjected to surgery of lower limbs with epidural anaesthesia were enrolled in this study. Treatments were administered at a dosage of 1.2 ml per metamera,including a test dose (3 mL) and the dose of fentanyl (100 mg). Patients were then randomly allocated to receive either Levobupivacaine (n = 49) or bupivacaine (N.= 47). The primary endpoint was sensory blockade (SB) duration. Secondary evaluations included motor blockade (MB), post-surgery analgesic medication usage, safety and the investigator global evaluation.

RESULTS

SB duration was similar for both interventions: 195 min (165-205) in the bupivacaine group versus 170 min (140-185) in the levobupivicaine group (log-rank test, P=0.884). However, the lack of MB as evaluated by the modified Bromage scale was significantly higher in the levobupivacaine group than in the bupivacaine group (39% vs 13%, P=0.017). Although no significant differences in MB duration were observed between the groups, a trend was observed in the levobupivacaine group, which had a lesser MB (P=0.093). Investigator satisfaction was high and was assessed to a similar extent for both interventions. Forty-one adverse events were detected in 28 patients, with no differences between groups: 15 (33%) with bupivacaine and 13 (27%) with levobupivacaine, P=0.516.

CONCLUSION

Although both interventions showed similar anaesthetic effects, a higher proportion of patients receiving levobupivacaine lacked MB.

Programmed cell death in zebrafish rohon beard neurons is influenced by TrkC1/NT-3 signaling

Rohon Beard (RB) cells are embryonic primary sensory neurons that are removed by programmed cell death during larval development in zebrafish. RB somatosensory functions are taken over by neurons of the dorsal root ganglia (DRG), suggesting that RB cell death may be triggered by the differentiation of these ganglia, as has been proposed to be the case in Xenopus. However, here we show that the timing of RB cell death correlates with reduced expression of trkC1, the receptor for neurotrophin NT-3, but not with the appearance of DRG, which differentiate only after most RB cells die. trkC1 is expressed in subpopulations of RB neurons during development, and cell death is initiated only in trkC1-negative neurons, suggesting a role for TrkC1 and its ligand, NT-3, in RB cell survival. In support of this, antibodies that deplete NT-3 induce RB cell death while exogenous application of NT-3 reduces death. In addition, we show that RB cell death can be prevented using a caspase inhibitor, zVADfmk, showing that during normal development, RB cells die by a caspase-dependent programmed cell death pathway possibly triggered by reduced signaling via TrkC1.

Anteroposterior patterning is required within segments for somite boundary formation in developing zebrafish

Somite formation involves the establishment of a segmental prepattern in the presomitic mesoderm, anteroposterior patterning of each segmental primordium and formation of boundaries between adjacent segments. How these events are co-ordinated remains uncertain. In this study, analysis of expression of zebrafish mesp-a reveals that each segment acquires anteroposterior regionalisation when located in the anterior presomitic mesoderm. Thus anteroposterior patterning is occurring after the establishment of a segmental prepattern in the paraxial mesoderm and prior to somite boundary formation. Zebrafish fss(−), bea(−), des(−) and aei(−) embryos all fail to form somites, yet we demonstrate that a segmental prepattern is established in the presomitic mesoderm of all these mutants and hox gene expression shows that overall anteroposterior patterning of the mesoderm is also normal. However, analysis of various molecular markers reveals that anteroposterior regionalisation within each segment is disturbed in the mutants. In fss(−), there is a loss of anterior segment markers, such that all segments appear posteriorized, whereas in bea(−), des(−) and aei(−), anterior and posterior markers are expressed throughout each segment. Since somite formation is disrupted in these mutants, correct anteroposterior patterning within segments may be a prerequisite for somite boundary formation. In support of this hypothesis, we show that it is possible to rescue boundary formation in fss(−) through the ectopic expression of EphA4, an anterior segment marker, in the paraxial mesoderm. These observations indicate that a key consequence of the anteroposterior regionalisation of segments may be the induction of Eph and ephrin expression at segment interfaces and that Eph/ephrin signalling subsequently contributes to the formation of somite boundaries.

Eph signaling is required for segmentation and differentiation of the somites

Somitogenesis involves the segmentation of the paraxial mesoderm into units along the anteroposterior axis. Here we show a role for Eph and ephrin signaling in the patterning of presomitic mesoderm and formation of the somites. Ephrin-A-L1 and ephrin-B2 are expressed in an iterative manner in the developing somites and presomitic mesoderm, as is the Eph receptor EphA4. We have examined the role of these proteins by injection of RNA, encoding dominant negative forms of Eph receptors and ephrins. Interruption of Eph signaling leads to abnormal somite boundary formation and reduced or disturbed myoD expression in the myotome. Disruption of Eph family signaling delays the normal down-regulation of her1 and Delta D expression in the anterior presomitic mesoderm and disrupts myogenic differentiation. We suggest that Eph signaling has a key role in the translation of the patterning of presomitic mesoderm into somites.

Effects of oral ciprofloxacin on aerobic gram-negative fecal flora in patients with cirrhosis: results of short- and long-term administration, with daily and weekly dosages

BACKGROUND/AIMS

Selective intestinal decontamination has been proposed to prevent spontaneous bacterial peritonitis in cirrhosis. Because of the cost of antibiotics and the development of resistant bacteria, we have evaluated the effect of different schemes and doses of oral ciprofloxacin on aerobic gram-negative fecal flora in cirrhotic patients.

METHOD

Twenty-nine cirrhotic patients were allocated to four groups to receive: Group 1: 500 mg/day for 2 weeks (six patients); Group 2: 1000 mg twice a week for 2 weeks (six patients); Group 3: 1000 mg once a week for 2 weeks (six patients); and Group 4: 1000 mg once a week for 12 weeks (11 patients). Quantitative analysis of the gram-negative fecal flora was performed before and 1 and 2 weeks after initiation of treatment in patients in Groups 1, 2 and 3 and before and 4, 8 and 12 weeks after initiation of treatment in patients in Group 4.

RESULTS

Complete eradication of gram-negative bacilli was observed in four of six patients in Group 1. In contrast, only one patient eradicated gram-negative bacilli in Group 2 and Group 3. In long-term administration of ciprofloxacin (Group 4), only two of 11 patients had persistent eradication of gram-negative bacilli. Four patients developed E. coli resistant to ciprofloxacin (one of them associated to resistant Klebsiella). No patient developed bacterial infection during the study period.

CONCLUSION

Oral ciprofloxacin administered in a weekly dose is ineffective in selective intestinal decontamination. Different mechanisms, including the emergence of ciprofloxacin-resistant organisms, could account for this failure. Therefore, our results suggest that weekly administration of ciprofloxacin is not useful in preventing spontaneous bacterial peritonitis.

[Evaluation of sensitivity, specificity and predictive value of six qualitative serological methods for the detection of Helicobacter pylori antibodies]

Screening tests for IG g antibodies against Helicobacter pylori are usefull for a long follow up of patients who were well eradicated. The aim of this study was to determinate and compared sensibility, specificity, positive and negative predictive value of six qualitative serological tests for IG g antibodies detection in the diagnosis of H. Pylori infections. Between May and October 1996 52 patients (30 males and 22 females; median age 42.4 years, range 21-68) with H. Pylori infection assessed on two antral and two corpus biopsies by means of Giema stain and a rapid urease test were tested for IG g antibodies detection. The serological tests used were: Inmunocomb II (Orgenics) Enzimo Inmuno Assay Inmunoadsorbent qualitative, Flex Pack (Smith Kline Diagnostics, Abbott) inmunocromatographic cualitative, Pylori Stat test (Biowhittaker) Enzimo Inmuno Assay (ELISA) qualitative, Premier (Meridian Diagnostics) Enzimo Inmuno Assay ELISA) qualitative. Pyloristest (Orion Diagnóstica) latex aglutination qualitative, H. Pylori (Bio Tre) Enzimo Inmuno Assay cualitative. 10 healthy subjects with negative gastric biopsies and negative rapid ureasa test were used as control group. The six evaluated serological tests have a comparable sensibility (89-95%) and specificity (77-83%) for the diagnosis of HP infection. The presence of specific HP antibodies in infected patients revealed a strong correlation with the histological demonstration of the microrganisms. We can recommend this qualitative serological tests due to their high sensibility and specificity, simplicity and low cost.

[Neuroradiological findings in 2 cases of Wilson disease with neurological involvement]

Wilson disease is an inborn error of copper metabolism that has neurological and hepatic manifestations. We report a 13 years old girl and a 12 years old boy with Wilson disease. In both patient, brain computed tomography and magnetic resonance imaging showed marked involvement of basal ganglia and other deep gray nuclei. Considering that this is a treatable disease, it should be included in the differential diagnosis of the so called "striatal necrosis of childhood".

[Clinical characteristics of the peripheral form of epidemic neuropathy in the province of Cienfuegos]

INTRODUCTION

From October 1992 to September 1993 clinical observations of the civil population of Cienfuegos revealed the presence of epidemic neuropathy (EN) reaching about 2,000 patients. The clinical manifestations were not uniform. Although numerous studies have been carried out in our country, none have established the characteristics of EN 'the peripheral form'.

MATERIAL AND METHODS

We studied the first 50 patients assisted by the neurological services of the clinical surgical hospital Dr. Gustavo Aldereguia Lima of Cienfuegos diagnosed of EN 'peripheral form' according to the procedure established by Ministry of Public Health of Cuba. A clinical history was made for each patient consisting of: General data, history of toxic, nutritional, malabsorption factors and chronic illnesses; symptoms and a neurological examinations. Laboratory test, in a group of patients, were done in sera, urine, cerebrospinal fluid (CSF), gastric juice and neurophysiological studies that included computerized evoked potentials and electroencephalograms registers.

RESULTS

Upon analysis of the clinical history, nutritional factors was common to all the patients associated to toxic and malabsorption. The clinical forms were neuropathy (NP) 48%, myeloneuropathy (MNP) 42% and myelopathy (MP) 10%. Retrobulbar optic neuropathy was observed in 42% of the patients and auditory neuropathy in 22%.

CONCLUSIONS

The clinical characteristics of NP, in our cases, indicated that this disease fundamentally affects the sensorial neurons and the sensitive peripheral nerves, bilaterally, symmetrically, distally and predominantly in lower limbs. The pathological process has been associated with a distal axonopathy. However, clinic signs of myelopathy can be found up to 40% frequently combined with neuropathy or in isolated form, and seems to affect the posterior and lateral columns of the spinal cord, mainly at thoraciclumbar level. Neuropathy of central nervous system is unknown since no patient has died of EN.

Hereditary angioedema: an infrequent cause of abdominal pain with ascites

Patients with hereditary angioedema have episodes of local swelling, usually affecting the face, extremities, upper airway, and gastrointestinal tract. Only infrequently does it cause recurrent abdominal pain (with or without ascites); however, because it has potentially life-threatening complications, an early diagnosis is important. We describe a case of type I hereditary angioedema (a quantitative deficit of C1 inhibitor), the sole initial symptom of which was severe recurrent and self-limited abdominal pain, accompanied by ascites during these episodes. During a 4-yr period of treatment with danazol, the patient was virtually asymptomatic, despite levels of C4 and C1 inhibitor that remained below normal limits, and there have been no major side effects that could be attributed to treatment with androgens.

Multiple cholesterol embolization syndrome: a lethal complication of vascular procedures. Report of two histologically proven cases

Two cases of multiple cholesterol embolization syndrome (MCES) leading to death are presented. Rarely described and labeled as a "great masquerader", its presence in the medical literature is growing, since it is best diagnosed, but despite the high frequency with which MCES may occur, only a few cases are reported. This syndrome is not universally recognised.

Fucosylated glycosphingolipids of human myeloid cells

Our efforts to determine the carbohydrate binding specificity of two myeloid-specific monoclonal antibodies (VIM-1 and VIM-10) resulted in the purification of three fucosylated glycosphingolipids from human chronic myelogenous leukemia cells. After repeated high-performance liquid chromatographic separations, two forms of fucosylated glycosphingolipids were resolved. VIM-1 and VIM-10 were found to bind to the heptaosylceramide Gal beta 1-4 (Fuc alpha 1-3)GlcNAc beta 1-3Gal beta 1-4GlcNAc beta 1-3Gal beta 1-4Glc beta 1-1Cer with the Le(x) (Lewis X) epitope, but not to either the hexaosylceramide Fuc alpha 1-2Gal beta 1-4(Fuc alpha 1-3)GlcNAc beta 1-3Gal beta 1-4Glc beta 1-1-Cer or the octaosylceramide Fuc alpha 1-2Gal beta 1-4(Fuc alpha 1-3)GlcNAc beta 1-3Gal beta 1-4GlcNAc beta 1-3Gal beta 1-4Glc beta 1-1Cer, each with the Le(y) (Lewis Y) epitope. The latter two glycosphingolipids are the first Le(y) antigens to be purified from human leukocytes and structurally characterized. Binding studies with a range of glycosphingolipids from myeloid cells and other biological sources demonstrated that VIM-1 and VIM-10 bind to Le(x) glycosphingolipids with five or more sugar residues, but not to a glycosphingolipid (III3Fuc-nLc6Cer) with an internal Le(x) trisaccharide.