Control Monoclonal Antibody Research Articles

A Capsular Polysaccharide-Specific Antibody Alters Streptococcus pneumoniae Gene Expression during Nasopharyngeal Colonization of Mice.

Pneumococcal conjugate vaccines (PCV) elicit opsonophagocytic (opsonic) antibodies to pneumococcal capsular polysaccharides (PPS) and reduce nasopharyngeal (NP) colonization by vaccine-included Streptococcus pneumoniae serotypes. However, nonopsonic antibodies may also be important for protection against pneumococcal disease. For example, 1E2, a mouse IgG1 monoclonal antibody (MAb) to the serotype 3 (ST3) PPS (PPS3), reduced ST3 NP colonization in mice and altered ST3 gene expression in vitro Here, we determined whether 1E2 affects ST3 gene expression in vivo during colonization of mice by performing RNA sequencing on NP lavage fluid from ST3-infected mice treated with 1E2, a control MAb, or phosphate-buffered saline. Compared to the results for the controls, 1E2 significantly altered the expression of over 50 genes. It increased the expression of the piuBCDA operon, which encodes an iron uptake system, and decreased the expression of dpr, which encodes a protein critical for resistance to oxidative stress. 1E2-mediated effects on ST3 in vivo required divalent binding, as Fab fragments did not reduce NP colonization or alter ST3 gene expression. In vitro, 1E2 induced dose-dependent ST3 growth arrest and altered piuB and dpr expression, whereas an opsonic PPS3 MAb, 5F6, did not. 1E2-treated bacteria were more sensitive to hydrogen peroxide and the iron-requiring antibiotic streptonigrin, suggesting that 1E2 may increase iron import and enhance sensitivity to oxidative stress. Finally, 1E2 also induced rapid capsule shedding in vitro, suggesting that this may initiate 1E2-induced changes in sensitivity to oxidative stress and gene expression. Our data reveal a novel mechanism of direct, antibody-mediated antibacterial activity that could inform new directions in antipneumococcal therapy and vaccine development.

Antibodies to Conserved Surface Polysaccharides Protect Mice Against Bacterial Conjunctivitis.

PurposeBacterial conjunctivitis is a major problem in ocular health. Little is known about protective immune effectors in the conjunctiva. We evaluated whether opsonic antibody to the conserved surface/capsular polysaccharide poly-N-acetyl glucosamine (PNAG) expressed by Streptococcus pneumoniae and Staphylococcus aureus was protective against bacterial conjunctivitis, as well as an antibody to the Pseudomonas aeruginosa surface polysaccharide alginate.MethodsBacteria were injected directly into the conjunctivae of either A/J mice or into conjunctivae of wild type C57Bl/6 mice for comparisons to responses of recombination activating gene 1-knock out (RAG 1 KO) or germ-free mice in the C57Bl/6 genetic background. Human IgG1 monoclonal antibodies (MAb) to either PNAG or alginate were administered as follows: direct injection of 10 μg into the conjunctivae or topical application onto the cornea 4, 24, and 32 hours post infection; or intraperitoneal injection of 200 μg 18 hours prior to and then 4, 24, and 32-hours postinfection. After 48 hours, eyes were scored for pathology, mice were euthanized, and CFU/conjunctiva was determined.ResultsAll methods of antibody administration reduced S. pneumoniae, S. aureus, or P. aeruginosa pathology and bacterial levels in the conjunctivae. Histopathologic analysis showed severe inflammatory cell infiltrates in conjunctivae of mice treated with control MAb, whereas immune mice showed only very mild cellular infiltration. The protective effect of MAb to PNAG was abolished in RAG 1 KO and germ-free mice.ConclusionsAntibodies to both PNAG and alginate demonstrated therapeutic efficacy in models of S. pneumoniae, S. aureus, and P. aeruginosa conjunctivitis, validating the protective capacity of antibodies to surface polysaccharides in distinct ocular tissues.

Neutralizing Alpha-Toxin Accelerates Healing of Staphylococcus aureus-Infected Wounds in Nondiabetic and Diabetic Mice.

Staphylococcus aureus wound infections delay healing and result in invasive complications such as osteomyelitis, especially in the setting of diabetic foot ulcers. In preclinical animal models of S. aureus skin infection, antibody neutralization of alpha-toxin (AT), an S. aureus-secreted pore-forming cytolytic toxin, reduces disease severity by inhibiting skin necrosis and restoring effective host immune responses. However, whether therapeutic neutralization of alpha-toxin is effective against S. aureus-infected wounds is unclear. Herein, the efficacy of prophylactic treatment with a human neutralizing anti-AT monoclonal antibody (MAb) was evaluated in an S. aureus skin wound infection model in nondiabetic and diabetic mice. In both nondiabetic and diabetic mice, anti-AT MAb treatment decreased wound size and bacterial burden and enhanced reepithelialization and wound resolution compared to control MAb treatment. Anti-AT MAb had distinctive effects on the host immune response, including decreased neutrophil and increased monocyte and macrophage infiltrates in nondiabetic mice and decreased neutrophil extracellular traps (NETs) in diabetic mice. Similar therapeutic efficacy was achieved with an active vaccine targeting AT. Taken together, neutralization of AT had a therapeutic effect against S. aureus-infected wounds in both nondiabetic and diabetic mice that was associated with differential effects on the host immune response.

Inhibition of Interleukin-6 Signaling with CNTO 328 Sensitizes Plasma Cell Dyscrasias to the Effects of Melphalan in Association with Suppression of Signaling through Protein Kinase B/Akt.

Abstract 1836Poster Board I-862 Background:The neutralizing anti-interleukin (IL)-6 monoclonal antibody (MAb) CNTO 328 acts in an additive to synergistic manner to enhance the activity of bortezomib and dexamethasone against models of multiple myeloma by suppressing several IL-6-induced anti-apoptotic signaling pathways. We therefore sought to evaluate the possibility that blockade of IL-6 signaling could also augment the activity of melphalan, and to determine the potential mechanisms underlying this interaction. Methods:A panel of myeloma cell lines was studied both in suspension and with bone marrow stromal cells to evaluate the activity of CNTO 328 with and without melphalan. The CNTO 328 + melphalan combination was also tested in primary cells from patients with a variety of plasma cell dyscrasias. Results:Treatment of IL-6-dependent KAS-6/1, INA-6, and ANBL-6 myeloma cell lines with CNTO 328 + melphalan reduced plasma cell viability in an additive-to-synergistic manner compared to melphalan with a control MAb. Isobologram analysis demonstrated that the combination was synergistic in KAS-6/1 cells regardless of the sequence of drug treatment (combination indices (CIs) from 0.275-0.607), although the strongest synergy was seen with CNTO 328 pretreatment (CIs from 0.275-0.493). These anti-proliferative effects were accompanied by an enhanced activation of drug-specific apoptosis, and this increased cell death was not rescued by the trophic effects of co-culture of plasma cells with the human-derived stromal cell line HS-5. CNTO 328 increased melphalan-mediated induction of both extrinsic, caspase-8-mediated apoptosis, as well as intrinsic, caspase-9-mediated death, which converged to produce increased levels of caspase-3 activity. Apoptosis was enhanced in part by CNTO 328-stimulated cleavage of Bid to tBid, and alterations in the phosphorylation status of BimEL, as well as increased conversion of Bak and, to a lesser extent, of Bax, to their active forms. Neutralization of IL-6 by CNTO 328 also suppressed signaling through the protein kinase B/Akt pathway, as evidenced by decreased levels of phospho-Akt, and decreased activation of several downstream Akt targets, including p70 S6 kinase and 4E-BP1. Importantly, CNTO 328 + melphalan showed enhanced anti-proliferative effects compared to melphalan and a control MAb against primary CD138+ plasma cells derived from patients with multiple myeloma, monoclonal gammopathy of undetermined significance, and amyloidosis, while demonstrating less toxicity to stromal cells. The enhanced effect of the CNTO 328 + melphalan combination was statistically significant compared to either drug alone (p<0.05) in CD138+ cells isolated from patients who had not received prior melphalan therapy. Conclusions:These studies provide a rationale for translation of CNTO 328 into the clinic in combination with melphalan-based therapies, including either high dose therapy in transplant-eligible patients, or standard dose melphalan-containing induction regimens in transplant-ineligible patients, such as with the combination of bortezomib, melphalan, and prednisone. Disclosures:Voorhees:Millennium Pharmaceuticals: Speakers Bureau; Celgene: Speakers Bureau. Xie:Centocor Ortho Biotech Inc.: Employment. Cornfeld:Centocor Ortho Biotech Inc.: Employment. Nemeth:Centocor Ortho Biotech Inc.: Employment.

Effect of Molecular Therapeutics on Liver Regeneration in a Murine Model

Unresectable metastatic colorectal cancer (CRC) can be rendered resectable with systemic chemotherapy in approximately 20% of cases. Most patients with metastatic CRC receive chemotherapy with the addition of targeted therapy with anti-vascular endothelial growth factor (VEGF) or anti-epidermal growth factor receptor (EGFR) antibodies. We sought to determine whether anti-VEGF receptor (VEGFR) or anti-EGFR therapy would impair liver regeneration after partial hepatectomy (PH) in mice. Mice underwent either 66% PH or sham laparotomy. In the first experiment, mice in the PH group were randomly assigned to receive daily intraperitoneal injections of monoclonal antibodies (MoABs) to murine VEGFR-2 or nonspecific MoABs (control). In the second experiment, mice in the PH group were randomly assigned to receive intraperitoneal injections of antimurine EGFR or nonspecific (control) MoABs. In both experiments, therapy was initiated the day before surgery and continued until the mice were killed on day 5. Livers were collected and processed. Anti-VEGFR-2 therapy slightly impaired liver regeneration and hepatic cell proliferation compared with control. Hematoxylin and eosin staining showed no differences in liver morphology. CD105 staining showed decreased levels of activated endothelium in livers in the VEGFR-2 MoAB group. VEGFR-2 MoAB therapy decreased the levels of the cell cycle regulators cyclin D1 and cyclin D3 and the regenerative cytokine interleukin-6. Anti-EGFR therapy had no effect on liver regeneration or cellular proliferation. Anti-VEGFR-2 therapy slightly impaired liver regeneration in this murine model, whereas anti-EGFR therapy had no effect on liver regeneration.

Quantitative Assessment of Protection in Experimental Syphilis

Protection in experimental rabbit syphilis has been previously assessed by lesion development following intradermal challenge with Treponema pallidum. We have recently reported that passive immunization using monoclonal antibody M131 conveys partial protection as evidenced by significant lesion delays following intradermal challenge. To determine whether such delays in time to lesion appearance corresponded to decreases in the numbers of spirochetes, we used real-time PCR to quantitate T. pallidum genomic DNA copy numbers in lesion biopsies taken throughout the course of lesion development. Three groups of animals were given one prechallenge passive immunization with immune rabbit serum (IRS), M131, or control monoclonal antibody (CMAb) and then challenged with treponemal admixtures of IRS or monoclonal antibody in normal rabbit serum (NRS). As compared to the CMAb NRS controls, delays in the mean time to lesion appearance of 5.8 days for IRS and 8.8 days for M131 were observed. At the earliest time point (10 days postchallenge), real-time PCR showed a mean T. pallidum DNA copy number per mug of rabbit DNA in the CMAb NRS group of 7.65 x 10(3) copies, while no T. pallidum DNA could be detected in the M131 group. At approximately the mean time to lesion appearance in the IRS and M131 groups (17 and 20 days, respectively), the numbers of T. pallidum DNA copies were still 5- and 30-fold less, respectively, than those in the control group at these times. By 30 days postchallenge, the T. pallidum DNA copy numbers were similar in all three groups. These findings indicate that the delays in appearance of syphilitic lesions conferred by IRS and M131 corresponded to a marked decrease in treponemal numbers during the course of lesion development.

Programmed cell death in Blastocystis hominis occurs independently of caspase and mitochondrial pathways

We demonstrated previously that a cytotoxic monoclonal antibody (MAb) 1D5 elicits a programmed cell death (PCD) response in Blastocystis hominis and showed that caspase-3-like protease influences but is not essential for PCD in MAb 1D5-treated B. hominis. We also showed that mitochondrial dysregulation played a role in cell death. In the current study, we further analyzed the signaling pathways involved in PCD mediated by MAb 1D5. B. hominis cells were treated with MAb 1D5 or control MAb 5, either with or without pretreatment with a pan-caspase inhibitor, zVAD.fmk, and/or a mitochondrial transition pore blocker, cyclosporine A (CA). Flow cytometric examination of cell size, mitochondrial membrane potential (Δ Ψ m), caspase activation and in situ DNA fragmentation showed that zVAD.fmk and CA, used independently or in combination, failed to inhibit MAb 1D5-mediated PCD. Interestingly, cell exposure to either inhibitor resulted in partial inhibition of DNA fragmentation while combined exposure of cells to inhibitors abolished DNA fragmentation completely. This study sheds new light on the conserved nature of PCD pathways in parasitic protozoa and is also the first report describing caspase- and mitochondria-independent cell death pathways in a protozoan parasite.

A humanized monoclonal antibody to carcinoembryonic antigen, labetuzumab, inhibits tumor growth and sensitizes human medullary thyroid cancer xenografts to dacarbazine chemotherapy

A variety of observations have shown that carcinoembryonic antigen (CEA) is associated with growth and metastasis of cancers, including correlation of CEA serum levels with poor clinical outcome, mediation of cell-cell adhesion by CEA, and involvement of CEA in the immune recognition of tumors and apoptotic pathways. The purpose of this study was to investigate the effect that an anti-CEA monoclonal antibody (MAb) may have on the growth of medullary thyroid cancer (MTC), a CEA-expressing tumor, alone and in combination with chemotherapy. Antitumor effects were evaluated in a nude mouse-human MTC xenograft model. Using the TT MTC cell line grown s.c., we compared tumor growth in untreated mice with that of mice given the humanized anti-CEA MAb labetuzumab or an isotype-matched control MAb. The effects of time of administration post-tumor injection, MAb dose response, specificity of response, and combination with dacarbazine (DTIC) chemotherapy were studied. The humanized anti-CEA MAb, labetuzumab, has direct, specific, antitumor effects in this model, without conjugation to a cytotoxic agent. In addition, labetuzumab sensitizes these tumor cells to chemotherapy with an effective drug in this model, DTIC, without increased toxicity. Significant delays in tumor growth were caused by the MAb therapy or chemotherapy alone; however, the combination of these agents was significantly more effective than either agent given as a monotherapy or use of an irrelevant MAb in this model. The superiority of the combined modality treatment argues for the integration of CEA MAb therapy into chemotherapeutic regimens for MTC management and possibly other CEA-expressing neoplasms.

Limited contribution of humoral immunity to the clearance of measles viremia in rhesus monkeys.

The development of an improved vaccine for controlling measles virus (MV) infections in the developing world will require an understanding of the immune mechanisms responsible for the clearance of this virus. To evaluate the role of humoral immunity in the containment of MV, rhesus monkeys were treated at the time of MV challenge with either anti-CD20 monoclonal antibody (MAb) infusion, to deplete B lymphocytes, or both anti-CD20 and anti-CD8 MAb, to deplete both B lymphocytes and CD8+ effector T lymphocytes. Although the MV-specific antibody response in CD20+ lymphocyte-depleted monkeys was delayed by >1 week, the kinetics of MV clearance did not differ from those for monkeys that received control MAb. Furthermore, unusual clinical sequelae of MV infection were not observed in these monkeys. In contrast, MV-infected rhesus monkeys depleted of both CD20+ and CD8+ lymphocytes had a prolonged duration of viremia and developed a desquamating skin rash. These findings indicate that humoral immunity plays a limited role in the control of MV replication in an MV-naive individual and suggest that new measles vaccination strategies should focus on the elicitation of cell-mediated immune responses, in addition to neutralizing antibodies, to facilitate rapid elimination of locally replicating virus.

Effects of a novel anti-exospore monoclonal antibody on microsporidial development in vitro.

The possible role of humoral antibodies in the immune response to microsporidiosis was studied using a novel anti-exospore monoclonal antibody (MAb) P5/H1 which recognised Encephalitozoon cuniculi. The effect of the P5/H1 MAb on microsporidial growth in vitro resulted in a reduction of the numbers of E. cuniculi spores in a Vero E6 cell-line culture. This reduction in the number of infected cells and the decrease of intracellular spores in infected cells was found when MAb P5/H1 was present in cultures, compared to cultures with an irrelevant isotype control MAb. Moreover, the presence of P5/H1 MAb increased the number of phagocytosed spores in macrophage cultures, and increased the activation of macrophages measured by nitrite oxide production. These results suggest a possible partial role of specific humoral antibodies in the protection against E. cuniculi infection.

Investigation of the role of CD8+ T cells in bovine tuberculosis in vivo.

Mycobacterium bovis is the causative agent of bovine tuberculosis (TB), and it has the potential to induce disease in humans. CD8(+) T cells (CD8 cells) have been shown to respond to mycobacterial antigens in humans, cattle, and mice. In mice, CD8 cells have been shown to play a role in protection against mycobacterial infection. To determine the role of CD8 cells in bovine TB in vivo, two groups of calves were infected with the virulent M. bovis strain AF2122/97. After infection, one group was injected with a CD8 cell-depleting monoclonal antibody (MAb), and the other group was injected with an isotype control MAb. Immune responses to mycobacterial antigens were measured weekly in vitro. After 8 weeks, the animals were killed, and postmortem examinations were carried out. In vitro proliferation responses were similar in both calf groups, but in vitro gamma interferon (IFN-gamma) production in 24-h whole-blood cultures was significantly higher in control cattle than in CD8 cell-depleted calves. Postmortem examination showed that calves in both groups had developed comparable TB lesions in the lower respiratory tract and associated lymph nodes. Head lymph node lesion scores, on the other hand, were higher in control calves than in CD8 cell-depleted calves. Furthermore, there was significant correlation between the level of IFN-gamma and the head lymph node lesion score. These experiments indicate that CD8 cells play a role in the immune response to M. bovis in cattle by contributing to the IFN-gamma response. However, CD8 cells may also play a deleterious role by contributing to the immunopathology of bovine TB.

Neutralization of hepatitis A virus (HAV) by an immunoadhesin containing the cysteine-rich region of HAV cellular receptor-1.

Hepatitis A virus (HAV) infects African green monkey kidney (AGMK) cells via the HAV cellular receptor-1 (havcr-1), a mucin-like type 1 integral-membrane glycoprotein of unknown natural function. The ectodomain of havcr-1 contains an N-terminal immunoglobulin-like cysteine-rich region (D1), which binds protective monoclonal antibody (MAb) 190/4, followed by an O-glycosylated mucin-like threonine-serine-proline-rich region that extends D1 well above the cell surface. To study the interaction of HAV with havcr-1, we constructed immunoadhesins fusing the hinge and Fc portion of human IgG1 to D1 (D1-Fc) or the ectodomain of the poliovirus receptor (PVR-Fc) and expressed them in CHO cells. These immunoadhesins were secreted to the cell culture medium and purified through protein A-agarose columns. In a solid-phase assay, HAV bound to D1-Fc in a concentration-dependent manner whereas background levels of HAV bound to PVR-Fc. Binding of HAV to D1-Fc was blocked by treatment with MAb 190/4 but not with control MAb M2, which binds to a tag epitope introduced between the D1 and Fc portions of the immunoadhesin. D1-Fc neutralized approximately 1 log unit of the HAV infectivity in AGMK cells, whereas PVR-Fc had no effect in the HAV titers. A similarly poor reduction in HAV titers was observed after treating the same stock of HAV with murine neutralizing MAbs K2-4F2, K3-4C8, and VHA 813. Neutralization of poliovirus by PVR-Fc but not by D1-Fc indicated that the virus-receptor interactions were specific. These results show that D1 is sufficient for binding and neutralization of HAV and provide further evidence that havcr-1 is a functional cellular receptor for HAV.

Tumor uptake of radioiodinated anti-human pulmonary surfactant-associated protein monoclonal antibody pe10 in nude mice bearing human pulmonary adenocarcinoma in combination with an unlabeled preload

This study assessed the potential use of radioimmunoscintigraphy of pulmonary alveolar Type II cells tumor with the radiolabeled anti-human surfactant-associated protein (SP) monoclonal antibody (MAb) PE 10 in combination with preloads of unlabeled MAb. The in vitro binding of iodine-125 ( 125I)-labeled MAb PE 10 (1 μg), which had a specific radioactivity of 400 MBq/mg, on human pulmonary papillary adenocarcinoma NCI-H441 cells that produced SP was investigated. In NCI-H441 tumor-bearing nude mice, the tumor uptake of 125I-MAb PE 10 (5 μg) was examined in combination with preloads of unlabeled MAb PE 10 (0, 5, 10, and 50 μg). An isotype-matched unassociated murine MAb was used as a control both in vitro and in vivo. 125I-MAb PE 10 showed specific cell binding compared with 125I-control MAb. Tumor uptake of 125I-MAb PE 10 in vivo reached a peak of 4.97±0.33% injected dose per gram (%ID/g) at 48 h postinjection. Preloads of 5 and 10 μg unlabeled MAb PE 10 significantly enhanced tumor uptake at 48 h postinjection ( 5.94±0.29% ID/ g and 5.72±0.29% ID/ g, respectively), whereas preload of 50 μg unlabeled MAb PE 10 significantly decreased tumor uptake ( 2.75±0.32% ID/g) at 48 h. Preload of 5 μg unlabeled MAb PE 10 significantly increased the tumor-to-blood radioactivity ratio at 48 h ( 2.39±0.16). Preloads of unlabeled control MAb did not cause any significant change in tumor uptake. Immunohistochemistry showed the intracellular and pericellular patterns of SP expression in tumor cells. In conclusion, radioimmunoscintigraphy with MAb PE 10 labeled with a γ-emitting radioiodine such as 123I might be a useful means of targeting pulmonary alveolar Type II tumor cells in combination with preloading with an optimal dose of the unlabeled MAb.

Therapeutic efficacy of mouse-human chimeric anti-ganglioside GM2 monoclonal antibody against multiple organ micrometastases of human lung cancer in NK cell-depleted SCID mice.

The development of distant metastases to multiple organs is a critical problem in the treatment of human lung cancer. In this study, we evaluated the therapeutic efficacy of a mouse-human chimeric anti-ganglioside GM2 (GM2) monoclonal antibody (MAb), KM966 against metastasis formation of GM2-positive human lung cancer cells inoculated intravenously (i.v.) into natural killer (NK) cell-depleted severe combined immunodeficient (SCID) mice. GM2-positive human small cell lung cancer (SCLC), SBC-3 cells (1 x 10(6)), injected through a tail vein into NK cell-depleted SCID mice, formed large number of metastatic colonies in the liver, kidneys and lymph nodes by 42 days after inoculation (day 42). KM966, but not control MAb, given on days 2 and 7, almost completely inhibited metastasis formation of SBC-3 cells in the liver, kidneys and lymph nodes in a dose-dependent fashion. Moreover, treatment with KM966 at advanced stages of metastasis (even from day 28) significantly suppressed multiple organ metastases of SBC-3 cells. The anti-metastatic effect of KM966 in vivo was mainly due to an antibody-dependent cell-mediated cytotoxicity (ADCC) reaction mediated by macrophages of the SCID mice. Our findings suggest that the mouse-human chimeric anti-GM2 MAb, KM966 may be useful for eradicating multiple organ micrometastases of lung cancer in humans.

Inhibition of experimental vasospasm with anti-intercellular adhesion molecule-1 monoclonal antibody in rats.

Inflammation may play a role in delayed chronic vasospasm after aneurysmal subarachnoid hemorrhage. We investigated the role of intercellular adhesion molecule-1 (ICAM-1) and macrophage/granulocyte infiltration in the rat femoral artery model of vasospasm using systemic administration of a murine anti-ICAM-1 monoclonal antibody (MAb). The femoral arteries (n = 72) in Sprague-Dawley rats (n = 36) were enclosed in latex pouches bilaterally. Autologous blood was injected into the pouch on one side, and saline was injected on the contralateral side. Chronic vessel narrowing was evaluated with the use of 29 rats, which were randomized into one of three groups for intraperitoneal injections: (1) anti-ICAM-1 MAb (2 mg/kg per dose, n = 10), (2) isotype-matched MAb (2 mg/kg per dose, n = 9), or (3) saline (n = 10), given at 3 hours and 3, 6, and 9 days after blood exposure. These rats were killed 12 days after blood exposure, and femoral artery lumen cross-sectional areas were determined by computerized image analysis. Saturation of ICAM-1 binding sites with this dosing schedule was evaluated by fluorescence-activated cell sorter (FACS) analysis of splenocytes. Immunohistochemical studies with objective cell counts were performed to evaluate macrophage/granulocyte infiltration at 24 hours in 7 rats, comparing anti-ICAM-1 MAb treatment (n = 4) with isotype-matched control MAb (n = 3). Animals treated with anti-ICAM-1 MAb showed a significant inhibition of arterial narrowing at 12 days (P = .0081), with lumen patency of 96.5 +/- 5.3% (mean +/- SEM), compared with 77.3 +/- 5.6% for isotype-matched MAb and 72.2 +/- 5.3% for saline-treated controls. FACS analysis of splenocytes from animals treated with anti-ICAM-1 MAb confirmed saturation of ICAM-1 binding sites. Vessels treated with anti-ICAM-1 MAb showed a significant decrease in inflammatory cell infiltrates, with objective macrophage/granulocyte counts of 31.3 +/- 26.6 (mean +/- SEM) per high-powered field, compared with 171.4 +/- 30.7 for isotype-matched control MAb (P = .0027). Anti-ICAM-1 MAb administered systemically starting 3 hours after blood exposure results in significant inhibition of chronic vasospasm in the rat femoral artery model and is correlated with a reduction in the number of infiltrating macrophages and granulocytes in the periadventitial region of blood-exposed arteries. We conclude that inflammatory changes associated with ICAM-1-mediated macrophage and granulocyte migration play an important role in the development of posthemorrhagic chronic vasospasm in this model.

Role of gamma interferon in the host immune and inflammatory responses to Pneumocystis carinii infection.

The role of gamma interferon (IFN-gamma) in host defense to Pneumocystis carinii was investigated by use of three different murine models of infection. C57BL/6 scid/scid (severe combined immunodeficient [SCID]) mice were given intratracheal inoculations of P. carinii and reconstituted with splenocytes from either mice with disrupted IFN-gamma genes (IFN-gamma-/- mice) or homozygous wild-type (IFN-gamma+/+) mice. Unreconstituted SCID mice had log10 7.08 +/- 0.13 P. carinii nuclei in their lungs at day 22 postinfection, whereas SCID mice reconstituted with splenocytes from either wild-type or IFN-gamma-/- mice had cleared the infection. However, there was a prolonged and exacerbated inflammatory response in the lungs of SCID mice reconstituted with IFN-gamma-/- splenocytes which was characterized by interstitial pneumonia, eosinophilia, and multinucleated giant cell formation. Similar results were found in C.B17 SCID mice reconstituted with CD4+ cells from P. carinii-immunized donors treated with neutralizing anti-IFN-gamma monoclonal antibody (MAb). These mice resolved their P. carinii infections; however, they also exhibited exacerbated lung pathology compared with mice treated with a control MAb. Finally, IFN-gamma-/- mice challenged intratracheally with P. carinii resolved their infection within 56 days as did IFN-gamma+/- mice. Furthermore, depletion of T cells in vivo with a MAb resulted in IFN-gamma-/- mice becoming susceptible to P. carinii infection. Together, these data indicate that IFN-gamma is not required for resolution of P. carinii infection; however, in the absence of IFN-gamma, there is a prolonged and exacerbated P. carinii-driven interstitial pneumonia characterized by eosinophilia and formation of multinucleated giant cells.

Immunohistologic analysis of renal CD40 and CD40L expression in lupus nephritis and other glomerulonephritides.

To investigate potential mechanisms by which CD40L-mediated signals may be involved in the pathogenesis of lupus glomerulonephritis (GN). Renal in situ CD40L and CD40 expression was examined in patient biopsy specimens. Immunohistochemical studies were performed on frozen sections utilizing anti-CD40L monoclonal antibody (MAb), anti-CD40 MAb, or control MAb. As controls, we analyzed normal kidney specimens and specimens obtained from patients with IgA nephropathy, focal segmental glomerulosclerosis, minimal change disease, idiopathic membranous GN, and antineutrophil cytoplasmic antibody-positive pauci-immune GN. Staining distribution was noted and staining intensity scored on a semiquantitative scale of 0 (no staining) to 3+ (intense staining). In normal kidney, CD40 was expressed on parietal epithelial cells, mesangial cells, endothelial cells, and distal tubules but not proximal tubules. Glomerular and tubular CD40 expression was markedly up-regulated in class III and class IV lupus GN, where there was intense staining of crescents, proximal and distal tubules, and interstitial mononuclear cells. In contrast, CD40 expression in class V lupus GN was similar to that in normal kidney. Interstitial mononuclear cells expressing CD40L were present in class IV lupus GN. However, these findings were not unique to lupus GN: up-regulation of CD40 and CD40L expression was similarly observed in other inflammatory renal diseases. This study shows that CD40 is expressed on a variety of renal parenchymal and non-parenchymal cells in normal kidney. Renal CD40 expression is up-regulated in class III and class IV lupus nephritis, as well as in other inflammatory renal diseases, and is associated with the presence of CD40L+ mononuclear cells.

Immunohistochemical evidence of disease recurrence after liver transplantation for primary biliary cirrhosis

Whether primary biliary cirrhosis (PBC) recurs after liver transplantation has remained an interesting and controversial issue; rejection, viral hepatitis, and drug effects all may mimic recurrent PBC histologically and biochemically. Furthermore, reliable clinical criteria for PBC recurrence are lacking. In this study, the issue of disease recurrence using a well-characterized monoclonal antibody (MAb), C355.1, that reacts with the immunodominant mitochondrial autoantigen of PBC (pyruvate dehydrogenase complex [PDC-E2]) was addressed. When used in an immunohistochemical assay, C355.1 produces intense apical staining of bile duct epithelium specifically in liver sections of patients with PBC and may be the earliest known marker of PBC. Immunohistochemical and histological analysis of serial liver biopsy specimens of 67 patients pre- and post-orthotopic liver transplantation (OLT), including 38 patients with PBC and 29 non-PBC liver disease controls, was performed. Sections were stained with MAb C355.1 or the control MAb C315 and analyzed to determine whether there was a recurrence of apical reactivity in the bile ducts of the posttransplantation biopsy specimens. The immunohistochemical staining was correlated with the histological findings and serum biochemistries at the time of the biopsy. Our data indicate that a significant number of patients who underwent transplantation for PBC (28 of 38) but not controls (0 of 29) develop a staining pattern of liver bile duct epithelium with MAb C355.1 that is indistinguishable from the pretransplantation pattern. Of the 28 patients with this apical staining pattern, 8 were characterized histologically as possible recurrent PBC, 2 as chronic rejection, 2 as acute rejection, 9 as nonspecific changes, 4 as normal or near normal, and 3 had other histological changes. Only 50% of the patients with apical C355.1 staining had liver enzyme levels suggestive of cholestasis. Thus, there appears to be immunohistochemical evidence that supports the concept of recurrence of PBC after OLT. The appearance of biliary epithelial abnormalities before the clinical appearance of disease is important not only for liver transplantation but also for understanding the natural history of PBC. (Hepatology 1996 Nov;24(5):1079-84)

Immunohistochemical evidence of disease recurrence after liver transplantation for primary biliary cirrhosis.

Whether primary biliary cirrhosis (PBC) recurs after liver transplantation has remained an interesting and controversial issue; rejection, viral hepatitis, and drug effects all may mimic recurrent PBC histologically and biochemically. Furthermore, reliable clinical criteria for PBC recurrence are lacking. In this study, the issue of disease recurrence using a well-characterized monoclonal antibody (MAb), C355.1, that reacts with the immunodominant mitochondrial autoantigen of PBC (pyruvate dehydrogenase complex [PDC-E2]) was addressed. When used in an immunohistochemical assay, C355.1 produces intense apical staining of bile duct epithelium specifically in liver sections of patients with PBC and may be the earliest known marker of PBC. Immunohistochemical and histological analysis of serial liver biopsy specimens of 67 patients pre- and post-orthotopic liver transplantation (OLT), including 38 patients with PBC and 29 non-PBC liver disease controls, was performed. Sections were stained with MAb C355.1 or the control MAb C315 and analyzed to determine whether there was a recurrence of apical reactivity in the bile ducts of the posttransplantation biopsy specimens. The immunohistochemical staining was correlated with the histological findings and serum biochemistries at the time of the biopsy. Our data indicate that a significant number of patients who underwent transplantation for PBC (28 of 38) but not controls (0 of 29) develop a staining pattern of liver bile duct epithelium with MAb C355.1 that is indistinguishable from the pretransplantation pattern. Of the 28 patients with this apical staining pattern, 8 were characterized histologically as possible recurrent PBC, 2 as chronic rejection, 2 as acute rejection, 9 as nonspecific changes, 4 as normal or near normal, and 3 had other histological changes. Only 50% of the patients with apical C355.1 staining had liver enzyme levels suggestive of cholestasis. Thus, there appears to be immunohistochemical evidence that supports the concept of recurrence of PBC after OLT. The appearance of biliary epithelial abnormalities before the clinical appearance of disease is important not only for liver transplantation but also for understanding the natural history of PBC.

Phenotypes correlating to metastatic properties of pancreas adenocarcinoma in vivo: the importance of surface sialyl Lewis(a) antigen.

Metastasis to the liver often occurs in patients during the natural course of pancreatic cancer. Using carcinoma cell lines established from 9 such patients, we examined phenotypes of cell lines to search for correlations with their potential to metastasize to the liver. Anti-asialo GMI-treated nude mice were used. PCI-43, -55, -24 and -6, in this order, had frequent metastases, while PCI-10, -19, -35, -64, and -66 did not. In vitro doubling time, surface expression of sialyl Lewis(a) (SLe(a)), VLA-4/6, LFA-I/3, CEA, E-selectin, VCAM-I, NCAM, Mac-I, HLA-ABC/ DR/DQ, ICAM-I/2, production of interleukin-I alpha, tumor necrosis factor-alpha, and matrix metalloproteinase, as well as susceptibility to cytotoxicity by natural killer cells, were all examined. Expression of surface SLea was significantly associated with metastasis; numbers of metastatic colonies of SLe(a)-positive and -negative cell lines were 21.6 +/- 33.9 and 6.5 +/- 14.3 (p < 0.01), respectively. Moreover, the intensity of surface SLe(a) expression of each PCI line correlated with the number of metastatic colonies in the liver. When anti-SLe(a) monoclonal antibody (MAb) was administered, the development of liver metastasis by PCI-43 cells was significantly repressed, as compared with a control MAb. Although a reverse correlation between surface ICAM-I expression and liver metastasis was noted, the species-restricted function of ICAM-I makes interpretation difficult. Collective evidence indicates that expression of SLe(a) is an important positive mediator in the hematogenous metastasis of pancreas carcinoma.