Phase I, first-in-human study of MSC-1 (AZD0171), a humanized anti-leukemia inhibitory factor monoclonal antibody, for advanced solid tumors.

BACKGROUND: Activation of leukemia inhibitory factor (LIF) is linked to an immunosuppressive tumor microenvironment (TME), with a strong association between LIF expression and tumor-associated macrophages (TAMs). MSC-1 (AZD0171) is a humanized monoclonal antibody that binds with high affinity to LIF, promoting antitumor inflammation through TAM modulation and cancer stem cell inhibition, slowing tumor growth. In this phase I, first-in-human, open-label, dose-escalation study, MSC-1 monotherapy was assessed in patients with advanced, unresectable solid tumors. MATERIALS AND METHODS: Using accelerated-titration dose escalation followed by a 3 + 3 design, MSC-1 doses of 75-1500 mg were administered intravenously every 3 weeks (Q3W) until progression or unmanageable toxicity. Additional patients were enrolled in selected cohorts to further evaluate safety, pharmacokinetics (PK), and pharmacodynamics after escalation to the next dose had been approved. The primary objective was characterizing safety and determining the recommended phase II dose (RP2D). Evaluating antitumor activity and progression-free survival (PFS) by RECIST v1.1, PK and immunogenicity were secondary objectives. Exploratory objectives included pharmacodynamic effects on circulating LIF and TME immune markers. RESULTS: Forty-one patients received treatment. MSC-1 monotherapy was safe and well tolerated at all doses, with no dose-limiting toxicities. The maximum tolerated dose was not reached and the RP2D was determined to be 1500 mg Q3W. Almost half of the patients had treatment-related adverse events (TRAEs), with no apparent trends across doses; no patients withdrew due to TRAEs. There were no objective responses; 23.7% had stable disease for ≥2 consecutive tumor assessments. Median PFS was 5.9 weeks; 23.7% had PFS >16 weeks. On-treatment changes in circulating LIF and TME signal transducers and activators of transcription 3 signaling, M1:M2 macrophage populations, and CD8+ T-cell infiltration were consistent with the hypothesized mechanism of action. CONCLUSIONS: MSC-1 was very well tolerated across doses, with prolonged PFS in some patients. Biomarker and preclinical data suggest potential synergy with checkpoint inhibitors.

LFA-1 as a key regulator of immune function: approaches toward the development of LFA-1-based therapeutics.

Over the past decade, Lymphocyte Function-Associated Antigen-1 (LFA-1, alphaLbeta2, CD11a/CD18) has emerged as an attractive therapeutic target for the treatment of multiple inflammatory diseases. Its established role in the trafficking and activation of leukocytes coupled with the recent elucidation of the global conformational changes that govern its function continue to drive pharmaceutical interest in this target. This sustained interest has led to the implementation of numerous drug discovery strategies leading to the development of antibodies, peptidomimetics, and small molecules that block LFA-1 function. The most successful demonstration of clinical efficacy to date has been with Raptiva, a humanized anti-LFA-1 antibody. In clinical trials of patients with moderate to severe psoriasis, improvements in several disease specific parameters including the Psoriasis Area and Severity Index (PASI) were observed. This review article will provide an overview of LFA-1 biology and structural regulation, as well as strategies that have been adopted in pursuit of effective therapies. Recent findings with different classes of small molecule antagonists will be highlighted with an emphasis on how their different mechanisms of action on the inserted domain (I domain) of CD11a have impacted our understanding of LFA-1 function and illuminated other potential avenues for therapeutic intervention.

A high endothelial cell-derived chemokine induces rapid, efficient, and subset-selective arrest of rolling T lymphocytes on a reconstituted endothelial substrate.

The homing of lymphocytes to secondary lymphoid organs is thought to involve the action of chemokines. Secondary lymphoid-tissue chemokine (SLC), a high endothelial venule (HEV)-associated chemokine, has emerged as a candidate for participating in this process. We now show that immobilized SLC strongly induces beta2 integrin-mediated binding of T lymphocytes of naive phenotype and B lymphocytes to ICAM-1 under static conditions. This effect is not mediated by beta2 integrin affinity modulation, because SLC does not elicit a beta2 integrin activation epitope (mAb24) on naive T lymphocytes. In a parallel plate flow chamber, lymphocytes rolling via L-selectin are rapidly arrested through beta2 integrins in a pertussis toxin-sensitive manner on a substrate consisting of L-selectin ligands (peripheral lymph node addressins) together with ICAM-1 and SLC. Naive T lymphocytes are arrested on the HEV substrate with sixfold higher efficiency than memory cells. Neutrophils roll, but are not arrested by SLC, whereas they respond to immobilized IL-8 with rapid arrest. Thus, our artificial HEV system recapitulates critical features of lymphocyte interactions with HEV in vivo. These observations strongly point to the participation of SLC in homing of lymphocytes to secondary lymphoid organs.

Ligation of L-selectin on T lymphocytes activates beta1 integrins and promotes adhesion to fibronectin.

Lymphocyte recirculation is dependent on families of adhesion molecules expressed on lymphocytes and their sequential interaction with ligands expressed on high endothelial venules in secondary lymphoid organs such as peripheral lymph nodes. By binding its carbohydrate-based ligands, L-selectin initiates this cascade of molecular interactions, supporting the rolling of lymphocytes along high endothelial venules. Subsequent activation of lymphocyte integrins leads to cell arrest followed by lymphocyte extravasation. Here, we demonstrate stimulated adhesion of PBL and Jurkat T cells to immobilized fibronectin following treatment with (1) GlyCAM-1, a physiologic ligand for L-selectin, and (2) cross-linked anti-L-selectin mAbs. We also utilize a solution binding assay to detect early changes in integrin activity, including affinity modulation and/or integrin clustering, and distinguish these from later postreceptor binding events such as changes in cell shape and spreading. With the Jurkat cell line, GlyCAM-1 and fucoidin (an L-selectin ligand mimetic) induce the binding of soluble fibronectin. In contrast, stimulation through the Jurkat TCR fails to promote binding to soluble ligand even though TCR cross-linking markedly enhances adhesion to immobilized fibronectin. These data suggest that L-selectin and the TCR promote adhesion through distinct mechanisms. Finally, we demonstrate that beta1 integrins are preferentially activated on naive T cells through the L-selectin pathway. Together with our previous studies showing similar activation of beta2 integrins on the naive T cell subset, these data suggest that signals delivered though L-selectin participate in the preferential recruitment of these cells to peripheral lymph nodes.

Factors that contribute to the transneuronal spread of herpes simplex virus.

In viral encephalitis and retinal necrosis, different herpes simplex virus (HSV) strains spread between neurons in the central nervous system (CNS) by distinctly different routes. The steps of viral infection and spread in a single neuron type and nearby glial cells in vivo have been determined for three different strains of HSV (F, H129, and McIntyre-B). The corneas of mice were inoculated with equivalent titers of the strains. Two to 5 days later, the animals were killed. The spread of viral proteins within trigeminal cells was examined using immuno- and electron microscopy and Western blots with anti-HSV polyclonal antiserum. McIntyre-B virus infection resulted in fewer labeled ganglion cells, possibly as a result of reduced viral production in the corneal epithelium or trigeminal ganglion cells. Although the McIntyre-B strain was at least as, if not more efficient, at retrograde transport than the other strains, the amount of McIntyre-B virus that was transported in the trigeminal roots in an anterograde direction was significantly less than the other strains. Uptake by ganglionic satellite cells was qualitatively similar for the three strains, but maturation and release of virus from satellite cells to other neurons were reduced in the McIntyre-B strain. These characteristics may account for the preferential retrograde transneuronal spread of McIntyre-B strain.

GlyCAM-1, a physiologic ligand for L-selectin, activates beta 2 integrins on naive peripheral lymphocytes.

Naive T cells are selectively recruited from the blood into peripheral lymph nodes during lymphocyte recirculation. L-selectin, a lectin-like receptor, mediates the initial attachment of lymphocytes to high endothelial venules (HEV) in lymph nodes. A subsequent step involving the activation of beta 2 integrins has been proposed to facilitate firm adhesion, but the activating signals are poorly understood. We report here that either antibody-mediated cross-linking of L-selectin on human lymphocytes or treatment of the cells with GlyCAM-1, an HEV-derived, secreted ligand for L-selectin, stimulates their binding to ICAM-1 through the beta 2 integrin pathway. Furthermore, GlyCAM-1 causes the rapid expression of a neoepitope on beta 2 integrins associated with a high-avidity state. Naive (CD45RA+), but not memory (CD45R0+) lymphocytes, respond to L-selectin cross-linking or GlyCAM-1 treatment. Thus, the complexing of L-selectin by specific ligands may provide key signals to naive lymphocytes, contributing to their selective recruitment into peripheral lymphoid organs.

The role of charge and multiple faces of the CD8 alpha/alpha homodimer in binding to major histocompatibility complex class I molecules: support for a bivalent model.

The CD8 dimer interacts with the alpha 3 domain of major histocompatibility complex class I molecules through two immunoglobulin variable-like domains. In this study a crystal structure-informed mutational analysis has been performed to identify amino acids in the CD8 alpha/alpha homodimer that are likely to be involved in binding to class I. Several key residues are situated on the top face of the dimer within loops analogous to the complementarity-determining regions (CDRs) of immunoglobulin. In addition, other important amino acids are located in the A and B beta-strands on the sides of the dimer. The potential involvement of amino acids on both the top and the side faces of the molecule is consistent with a bivalent model for the interaction between a single CD8 alpha/alpha homodimer and two class I molecules and may have important implications for signal transduction in class I-expressing cells. This study also demonstrates a role for the positive surface potential of CD8 in class I binding and complements previous work demonstrating the importance of a negatively charged loop on the alpha 3 domain of class I for CD8 alpha/alpha-class I interaction. We propose a model whereby residues located on the CDR-like loops of the CD8 homodimer interact with the alpha 3 domain of MHC class I while amino acids on the side of the molecule containing the A and B beta-strands contact the alpha 2 domain of class I.

Monostotic fibrous dysplasia of the thoracic spine.

Fibrous dysplasia involving the thoracic spine is very rare. This patient had monostotic fibrous dysplasia involving the vertebral body, posterior elements, and right seventh rib with focal neurologic signs. The radiographic and bone scan findings are shown. The patient was treated successfully with tumor resection and arthrodesis using combined anterior and posterior approaches. Although fibrous dysplasia is classified as a benign process, clear margins of resection are required to prevent recurrence.

Effects of a home visiting program on prenatal care and birthweight: a case comparison study.

Recent reports have stressed the importance of social support services to the health and well being of pregnant women and their newborns. The impact of paraprofessional support services on the amount of prenatal care received and birthweight was studied in a sample of 111 low-income women. Paraprofessionals were women who had been on public assistance and successfully attained health and human services for themselves and their infants. They were similar to the patients they served in educational background and ethnicity. A six-week training program prepared them to counsel and assist pregnant women with health and social services, housing, food, transportation and other basic necessities. Women attending a publically-funded prenatal clinic were randomly assigned to a paraprofessional. A comparison group matched for ethnicity, parity and trimester entering prenatal care was also selected. Women followed by a paraprofessional had significantly more prenatal appointments (8.0 vs 6.5 visits) and infants with average higher birthweight (3125 grams) over the matched comparison group (3273 grams). While intensity of contact with a paraprofessional contributed significantly to the amount of prenatal care received by patients of paraprofessionals, the mechanism for improvement in birthweight is unknown.

Cell-cell adhesion mediated by CD8 and human histocompatibility leukocyte antigen G, a nonclassical major histocompatibility complex class 1 molecule on cytotrophoblasts.

The lymphocyte differentiation marker CD8 acts as a coreceptor with the T cell receptor (TCR) during recognition of peptide presented by major histocompatibility complex (MHC) class I molecules. The functions of CD8 in the TCR complex are thought to be signaling through the association of CD8 with the protein tyrosine kinase p56lck and adhesion to MHC class I through the alpha 3 domain. While the ability of the CD8 alpha/alpha homodimer to bind to classical MHC class I molecules has been shown, it is unclear whether CD8 can also bind nonclassical molecules. Of particular interest is human histocompatibility leukocyte antigen (HLA)-G which is expressed on placental cytotrophoblast cells. These cells do not express HLA-A, -B and -C molecules. In this report, we demonstrate that CD8 can bind to HLA-G. It is possible, therefore, that a cell bearing CD8 may interact with HLA-G-expressing cells.

Development of a paraprofessional home visiting program for low-income mothers and infants.

This article reports the development of a paraprofessional home visiting program based upon empirically documented client needs, maintenance of the qualities of mutuality and cooperation found in the indigenous paraprofessionals, and methods of ongoing program revision. Three studies are described that suggested four areas of program emphasis: (1) continuity of services from pregnancy through infancy, (2) needs assessment procedures sensitive to a broad range of health and social problems, (3) an ongoing personal relationship with an indigenous paraprofessional, and (4) reduction of barriers to prenatal care inherent in the health care system itself. We provide examples of program application and revision through training of paraprofessionals, case management procedures, and interventions within the perinatal health care system.

Effects of social supports on attitudes, health behaviors and obtaining prenatal care.

The influence of social support on attitudes, health behaviors and attaining prenatal care was assessed in 300 postpartum patients. Demographic, medical, sociocultural, attitudinal and behavioral factors were assessed by interview and review of the medical chart. Three discrete social support factors (intimacy, comfort, security) were identified by factor analysis. The presence of social support was correlated with positive prenatal attitudes, not using drugs, and adequate health resources. Stepwise multiple-regression analysis demonstrated that one social support factor (intimacy), two health behaviors (not drinking and not smoking while pregnant), and parity accounted for 22% of the variance in amount of prenatal care.

Issues in adolescent gynecologic care.

Adolescence is a period of transition from childhood to adulthood. During this period, the potential for high-risk behaviors that may negatively impact on gynecologic health care are great. To enhance the potential for optimal care of this group of individuals, the physician must understand that (1) adolescents must be active participants in the decision making concerning their gynecologic health, (2) adolescents need to be able to communicate their concerns about gynecologic health in a confidential forum, and (3) there are areas of early gynecologic development and maturation for which anticipatory guidance is required.

Enhancing the adolescent reproductive process: efforts to implement a program for black adolescent fathers.

The importance of adolescent fathers participating more fully in pregnancy and childrearing has been emphasized increasingly in the literature. This article describes the development and evaluation of childbearing clinical services designed for adolescent fathers. This multidisciplinary effort used an action research model that integrates empirical research into ongoing programs, continuously monitoring progress. It is comprised of five elements: population description, determination of clients' health needs, assessment and development of resources, evaluation of program services, and monitoring of outcomes. Although the study was not designed exclusively for black adolescents, 95% of the individuals who participated were black. The cultural composition of the study population suggests and impact on the findings. Suggestions are made for future program efforts with adolescent parents.

Effective utilization and evaluation of indigenous health care workers.

The use of indigenous health care workers (IHCWs), who were key elements in community health care programs in the United States in the 1960s, has gone in and out of fashion in subsequent years. The author and his colleagues recently established a service program at Wayne State University's Institute of Maternal and Child Health that employs IHCWs. Characterizations of IHCWs in previous health care programs were reviewed in the process of developing criteria and guidelines for the recruitment, selection, training, employing, and evaluating these workers in the Institute's program. The unique applicability of indigenousness to the delivery of health care services is addressed in terms of the rationale for the use of IHCWs as well as criteria for their success, benefits and problems encountered in the use of these workers, and deficiencies in evaluations of IHCWs. A model of program evaluation, action research, is proposed that assesses the processes and outcomes of providing health services by indigenous paraprofessionals.

A secreted form of the human lymphocyte cell surface molecule CD8 arises from alternative splicing.

The human lymphocyte differentiation antigen CD8 is encoded by a single gene that gives rise to a 33- to 34-kDa glycoprotein expressed on the cell surface as a dimer and in higher molecular mass forms. We demonstrate that the mRNA is alternatively spliced so that an exon encoding a transmembrane domain is deleted. This gives rise to a 30-kDa molecule that is secreted and exists primarily as a monomer. mRNA corresponding to both forms is present in peripheral blood lymphocytes, Con A-activated peripheral blood lymphocytes, and three CD8+ T-cell lines, with the membrane form being the major species. However, differences in the ratio of mRNA for membrane CD8 and secreted CD8 exist. In addition, the splicing pattern we observe differs from the pattern found for the mouse CD8 gene. This mRNA is also alternatively spliced, but an exon encoding a cytoplasmic region is deleted, giving rise to a cell surface molecule that differs in its cytoplasmic tail from the protein encoded by the longer mRNA. Neither protein is secreted. This is one of the first examples of a different splicing pattern between two homologous mouse and human genes giving rise to very different proteins. This represents one mechanism of generating diversity during speciation.