Systematic Literature Review of the Prevalence and Prognostic Value of Delta-Like Ligand 3 Protein Expression in Small Cell Lung Cancer

BACKGROUND

Delta-like ligand 3 (DLL3), a member of the Notch pathway, has been identified as a potential therapeutic target as it is highly expressed in small cell lung cancer (SCLC), a subtype accounting for 15% of lung cancer cases.

OBJECTIVE

A systematic literature review (SLR) was conducted to understand the prevalence and prognostic impact of DLL3 expression on survival of patients with SCLC and treatment response.

PATIENTS AND METHODS

Systematic literature searches were conducted across multiple databases to capture studies of any SCLC population that evaluated DLL3 expression. Specific outcomes of interest included prevalence of DLL3 expression, method of expression analysis, and impact on outcome, including treatment response and survival (overall, progression-free, disease-free) according to varying levels of DLL3 expression/positivity. Standard risk of bias tools were used to evaluate study quality.

RESULTS

Among the 30 included studies, the most common DLL3 testing method was immunohistochemistry (N = 26, 86.7%). For comparability, results focused on the 13 (22.3%) studies that used the Ventana DLL3 (SP347) immunohistochemistry assay. The prevalence of DLL3 positivity ranged from 80.0-93.5% for studies using a threshold of ≥ 1% of tumor cells (N = 4) and 58.3-91.1% for studies with a ≥ 25% threshold (N = 4). DLL3 expression was generally categorized as high using cutoffs of ≥ 50% (prevalence range: 45.8-79.5%; N = 6) or ≥ 75% (prevalence range: 47.3-75.6%; N = 5) of cells with positivity. Two studies used an H-score of ≥ 150 to define high DLL3 expression with prevalence ranging from 33.3-53.1%. No consistent associations were seen between DLL3 expression level and patient age, sex, smoking history, or disease stage. Two studies reported change in DLL3 expression category (high versus low) before and after chemotherapy. No statistically significant differences were reported between DLL3 expression groups and survival (overall, progression-free, or disease-free) or treatment response.

CONCLUSIONS

There is a high prevalence of DLL3 expression in SCLC. Further research and analytical methods may help to characterize different populations of patients with SCLC based on DLL3 expression. While no significant prognostic factor in the included studies was identified, additional cohort studies using standardized methodology, with longer follow-up, are needed to better characterize any potential differences in patient survival or response by DLL3 expression level in SCLC.

Interim analysis of ibrutinib plus paclitaxel for patients with advanced urothelial carcinoma previously treated with platinum-based chemotherapy

4522

Background: Patients (pts) with advanced urothelial carcinoma (aUC) who progressed after platinum-based chemotherapy (PBCT) have a median overall survival (OS) of ~6 mo on CT and 8-10 mo on novel immune checkpoint inhibitors (ICIs). Treatment (tx) with ibrutinib (ibr), a first-in-class, once-daily inhibitor of Bruton’s tyrosine kinase (BTK) with immunomodulatory properties, plus paclitaxel (pac) may improve outcomes for pts with aUC. Methods: Pts with aUC who had 1-2 prior tx (≥1 PBCT and/or ICIs) formed one cohort of this phase 1b/2 study. Recommended phase 2 dose per phase 1b was ibr 840 mg/d + weekly pac 80 mg/m2 in 21-d cycles; starting ibr dose of 560 mg/d. nanoString gene expression assay (NanoString Technologies) was used for preliminary assessment of ibr-targeted kinases in baseline tumor biopsies. Results: This interim analysis included the first 29 pts treated (ibr 840/560 mg/d, n = 25/4; median age 67 y). 52% had 2 prior regimens (prior PD-L1 inhibitors, 100%). Median time on study/tx was 7.2/2.3 mo (max tx: 11.5 mo). Unconfirmed overall response rate (ORR) was 41% (complete/partial response: 10%/31%). Disease control rate was 62%. ORR was 71% for 7 pts with only lymph node metastases; ORR was 36% for 14 pts with 1 prior tx and 47% for 15 pts with 2 prior tx. Median duration of response was 4.2 mo (90% CI: 1.9-7.1). Median progression-free survival was 3.6 mo (90% CI: 1.6-5.4). Median OS was 14.7 mo (90% CI: 7.7-15.9). Follow-up is ongoing for durability/survival with 6 pts alive without progression, including 4 still on ibr. 76% of pts had grade ≥3 adverse events (AEs); 4 discontinued ibr + pac due to AEs and 1 had major hemorrhage. Pac exposure was not impacted by ibr; pac geometric mean Cmax (2066 ng/mL) and AUC0-∞ (3813 ng·h/mL) were consistent with historical data. Preliminary tumor biopsy data showed a nonsignificant trend of higher BTK/ITK/BMX expression in tx responders; analyses are ongoing. Conclusions: Ibr + pac shows promising results for ORR/OS in pts with aUC previously treated with PBCT and ICIs. No unexpected safety signals were seen; ibr + pac seemed tolerable. Follow-up of these and additional pts will support the activity and safety of ibr + pac in this study. Clinical trial information: NCT02599324.

Interim analysis of ibrutinib plus paclitaxel for patients with metastatic urothelial carcinoma previously treated with platinum-based chemotherapy

365

Background: In patients (pts) with advanced urothelial carcinoma (aUC) who progressed after platinum-based chemotherapy (CT), median overall survival (OS) is ~6 mo with CT and 8-10 mo with novel immune checkpoint inhibitors (ICIs). Ibrutinib (ibr), a first-in-class, once-daily, inhibitor of Bruton’s tyrosine kinase (BTK) with immunomodulatory properties, plus paclitaxel (pac) may be an effective treatment (tx) for pts with UC. Methods: One cohort in this phase 1b/2 study assessed ibr + pac in pts who had 1-2 prior tx (≥1 platinum-based and/or ICIs) with aUC. Recommended phase 2 dose per Phase 1b was ibr 840 mg/d + weekly pac 80 mg/m2 in 21-d cycles; starting ibr dose: 560 mg/d. Preliminary BTK/other kinase assessment in baseline tumor biopsies was done by NanoString gene expression assay. Results: Based on interim analysis of the first 29 pts treated (ibr 840/560 mg/d, n = 25/4), median time on study/ tx was 7.2/2.3 mo (max tx: 11.5 mo). Median age was 67 y; 52% had 2 prior regimens (prior PDL-1 inhibitors, 100%). Unconfirmed ORR was 41% (complete/partial response: 10%/31%) and disease control rate was 62%. ORR was 71% for subset of 7 pts with only lymph node metastases, and 36% for 14 pts with 1 prior tx and 47% for 15 with 2 prior tx. Median duration of response was 4.2 mo (90% CI: 1.9, 7.1). Median PFS was 3.6 mo (90% CI: 1.6, 5.4) and median OS was 14.7 mo (90% CI: 7.7, 15.9). Follow-up for durability/survival is ongoing with 6 pts alive without progression, with 4 still on ibr tx. 76% of pts had grade ≥3 adverse events (AEs); 4 discontinued ibr + pac due to AEs and 1 had major hemorrhage. Pac exposure was not impacted by ibr; pac geometric mean Cmax (2066 ng/mL) and AUC0-∞ (3813 ng.h/mL) were consistent with historical data. Preliminary tumor biopsy data showed a non-significant trend of higher BTK/ITK/BMX expression in responders; analyses are ongoing for ibr-targeted kinases. Conclusions: These results indicate that ibr + pac shows promising results for ORR and OS in pts with aUC previously treated with platinum-based CT and ICIs. There were no unexpected safety signals; ibr + pac seemed tolerable. Follow up of these and additional pts will support the efficacy and safety of ibr + pac in this study. Clinical trial information: NCT02599324.

Affinity Maturation of the Anti-Citrullinated Protein Antibody Paratope Drives Epitope Spreading and Polyreactivity in Rheumatoid Arthritis

OBJECTIVE

Anti-citrullinated protein antibodies (ACPAs) are a hallmark of rheumatoid arthritis (RA). While epitope spreading of the serum ACPA response is believed to contribute to RA pathogenesis, little is understood regarding how this phenomenon occurs. This study was undertaken to analyze the antibody repertoires of individuals with RA to gain insight into the mechanisms leading to epitope spreading of the serum ACPA response in RA.

METHODS

Plasmablasts from the blood of 6 RA patients were stained with citrullinated peptide tetramers to identify ACPA-producing B cells by flow cytometry. Plasmablasts were single-cell sorted and sequenced to obtain antibody repertoires. Sixty-nine antibodies were recombinantly expressed, and their anticitrulline reactivities were characterized using a cyclic citrullinated peptide enzyme-linked immuosorbent assay and synovial antigen arrays. Thirty-six mutated antibodies designed either to represent ancestral antibodies or to test paratope residues critical for binding, as determined from molecular modeling studies, were also tested for anticitrulline reactivities.

RESULTS

Clonally related monoclonal ACPAs and their shared ancestral antibodies each exhibited differential reactivity against citrullinated antigens. Molecular modeling identified residues within the complementarity-determining region loops and framework regions predicted to be important for citrullinated antigen binding. Affinity maturation resulted in mutations of these key residues, which conferred binding to different citrullinated epitopes and/or increased polyreactivity to citrullinated epitopes.

CONCLUSION

These results demonstrate that the different somatic hypermutations accumulated by clonally related B cells during affinity maturation alter the antibody paratope to mediate epitope spreading and polyreactivity of the ACPA response in RA, suggesting that these may be key properties that likely contribute to the pathogenicity of ACPAs.

T Cell-Dependent Affinity Maturation and Innate Immune Pathways Differentially Drive Autoreactive B Cell Responses in Rheumatoid Arthritis

OBJECTIVE

Rheumatoid arthritis (RA) is characterized by the activation of B cells that produce anti-citrullinated protein antibodies (ACPAs) and rheumatoid factors (RFs), but the mechanisms by which tolerance is broken in these B cells remain incompletely understood. We undertook this study to investigate whether ACPA+ and RF+ B cells break tolerance through distinct molecular mechanisms.

METHODS

We developed antigen-tetramers to isolate ACPA+ and RF+ B cells and performed single-cell RNA sequencing on 2,349 B cells from 6 RA patients and 1 healthy donor to analyze their immunoglobulin repertoires and transcriptional programs. Prominent immunoglobulins were expressed as monoclonal antibodies and tested for autoantigen reactivity.

RESULTS

ACPA+ and RF+ B cells were enriched in the peripheral blood of RA patients relative to healthy controls. Characterization of patient-derived monoclonal antibodies confirmed ACPA and RF targeting of tetramer-specific B cells at both antigen-inexperienced and affinity-matured B cell stages. ACPA+ B cells used more class-switched isotypes and exhibited more somatic hypermutations relative to RF+ B cells, and these differences were accompanied by down-regulation of CD72 and up-regulation of genes that promote class-switching and T cell-dependent responses. In contrast, RF+ B cells expressed transcriptional programs that stimulate rapid memory reactivation through multiple innate immune pathways. Coexpression analysis revealed that ACPA+ and RF+ B cell-enriched genes belong to distinct transcriptional regulatory networks.

CONCLUSION

Our findings suggest that ACPA+ and RF+ B cells are imprinted with distinct transcriptional programs, which suggests that these autoantibodies associated with increased inflammation in RA arise from 2 different molecular mechanisms.

Circulating plasmablasts are elevated and produce pathogenic anti-endothelial cell autoantibodies in idiopathic pulmonary arterial hypertension

Idiopathic pulmonary arterial hypertension (IPAH) is a devastating pulmonary vascular disease in which autoimmune and inflammatory phenomena are implicated. B cells and autoantibodies have been associated with IPAH and identified as potential therapeutic targets. However, the specific populations of B cells involved and their roles in disease pathogenesis are not clearly defined. We aimed to assess the levels of activated B cells (plasmablasts) in IPAH, and to characterize recombinant antibodies derived from these plasmablasts. Blood plasmablasts are elevated in IPAH, remain elevated over time, and produce IgA autoantibodies. Single-cell sequencing of plasmablasts in IPAH revealed repertoires of affinity-matured antibodies with small clonal expansions, consistent with an ongoing autoimmune response. Recombinant antibodies representative of these clonal lineages bound known autoantigen targets and displayed an unexpectedly high degree of polyreactivity. Representative IPAH plasmablast recombinant antibodies stimulated human umbilical vein endothelial cells to produce cytokines and overexpress the adhesion molecule ICAM-1. Together, our results demonstrate an ongoing adaptive autoimmune response involving IgA plasmablasts that produce anti-endothelial cell autoantibodies in IPAH. These antibodies stimulate endothelial cell production of cytokines and adhesion molecules, which may contribute to disease pathogenesis. These findings suggest a role for mucosally-driven autoimmunity and autoimmune injury in the pathogenesis of IPAH.

Plasmablast antibody repertoires in elderly influenza vaccine responders exhibit restricted diversity but increased breadth of binding across influenza strains

Seasonal influenza vaccines elicit antibody responses that can prevent infection, but their efficacy is reduced in the elderly. While a subset of elderly individuals can still mount sufficient vaccine-induced antibody responses, little is known about the properties of the vaccine-induced antibody repertoires in elderly as compared to young responders. To gain insights into the effects of aging on influenza vaccine-induced antibody responses, we used flow cytometry and a cell-barcoding method to sequence antibody heavy and light chain gene pairs expressed by individual blood plasmablasts generated in response to influenza vaccination in elderly (aged 70-89) and young (aged 20-29) responders. We found similar blood plasmablast levels in the elderly and young responders seven days post vaccination. Informatics analysis revealed increased clonality, but similar heavy chain V(D)J gene usage in the elderly as compared to young vaccine responders. Although the elderly responders exhibited decreased antibody sequence diversity and fewer consequential mutations relative to young responders, recombinant antibodies from elderly responders bound a broader range of influenza strain HAs. Thus elderly influenza vaccine responders mount plasmablast responses with restricted diversity but with an increased breadth of binding across influenza strains. Our results suggest that the ability to generate plasmablast responses encoding cross-strain binding antibodies likely represents a mechanism important to vaccine responses in the elderly.

Large-scale sequencing of antibody responses to Borrelia burgdorferi infection (MPF5P.743)

Patients with Lyme disease present with protean manifestations and kinetics of disease, and these differences cannot be solely attributed to pathogen load or strain. Better understanding of antibody-mediated immunity in the human host is crucial for developing improved diagnostics and could provide insights into immune targeting of B. burgdorferi antigens associated with successful clearance of infection. We have developed an “antibody repertoire capture” (ARC) strategy that utilizes DNA barcodes to enable large-scale sequence analysis of the paired heavy-chain (HC) and light-chain (LC) immunoglobulin (Ig) genes expressed by individual Ig-expressing cells. This method allows us to generate evolutionary trees of the paired (HC+LC) repertoires and thus identify and recombinantly express the affinity-matured antibodies that are likely to drive immune protection and pathogenicity. We have applied ARC to peripheral blood plasmablasts from patients with early (weeks-long) and late (months-long) untreated B. burgdorferi infections. The size and number of clonally expanded Ig families was significantly greater in infections that went untreated for many months. Recombinant mAbs derived from these sequences bound to both host- and pathogen-associated antigens. These human plasmablast-derived mAbs provide us with a powerful tool to interrogate the functions of host antibodies in vitro and in animal models of infection, and may prove to have diagnostic or therapeutic potential.

Mass cytometry analysis shows that a novel memory phenotype B cell is expanded in multiple myeloma

It would be very beneficial if the status of cancers could be determined from a blood specimen. However, peripheral blood leukocytes are very heterogeneous between individuals, and thus high-resolution technologies are likely required. We used cytometry by time-of-flight and next-generation sequencing to ask whether a plasma cell cancer (multiple myeloma) and related precancerous states had any consistent effect on the peripheral blood mononuclear cell phenotypes of patients. Analysis of peripheral blood samples from 13 cancer patients, 9 precancer patients, and 9 healthy individuals revealed significant differences in the frequencies of the T-cell, B-cell, and natural killer-cell compartments. Most strikingly, we identified a novel B-cell population that normally accounts for 4.0% ± 0.7% (mean ± SD) of total B cells and is up to 13-fold expanded in multiple myeloma patients with active disease. This population expressed markers previously associated with both memory (CD27(+)) and naïve (CD24(lo)CD38(+)) phenotypes. Single-cell immunoglobulin gene sequencing showed polyclonality, indicating that these cells are not precursors to the myeloma, and somatic mutations, a characteristic of memory cells. SYK, ERK, and p38 phosphorylation responses, and the fact that most of these cells expressed isotypes other than IgM or IgD, confirmed the memory character of this population, defining it as a novel type of memory B cells.

Barcode-enabled sequencing of plasmablast antibody repertoires in rheumatoid arthritis

OBJECTIVE

A hallmark of rheumatoid arthritis (RA) is the production of autoantibodies, including anti-citrullinated protein antibodies (ACPAs). Nevertheless, the specific targets of these autoantibodies remain incompletely defined. During an immune response, B cells specific for the inciting antigen(s) are activated and differentiate into plasmablasts, which are released into the blood. We undertook this study to sequence the plasmablast antibody repertoire to define the targets of the active immune response in RA.

METHODS

We developed a novel DNA barcoding method to sequence the cognate heavy- and light-chain pairs of antibodies expressed by individual blood plasmablasts in RA. The method uses a universal 5' adapter that enables full-length sequencing of the antibodies' variable regions and recombinant expression of the paired antibody chains. The sequence data sets were bioinformatically analyzed to generate phylogenetic trees that identify clonal families of antibodies sharing heavy- and light-chain VJ sequences. Representative antibodies were expressed, and their binding properties were characterized using anti-cyclic citrullinated peptide 2 (anti-CCP-2) enzyme-linked immunosorbent assay (ELISA) and antigen microarrays.

RESULTS

We used our sequencing method to generate phylogenetic trees representing the antibody repertoires of peripheral blood plasmablasts from 4 individuals with anti-CCP+ RA, and recombinantly expressed 14 antibodies that were either "singleton" antibodies or representative of clonal antibody families. Anti-CCP-2 ELISA identified 4 ACPAs, and antigen microarray analysis identified ACPAs that differentially targeted epitopes on α-enolase, citrullinated fibrinogen, and citrullinated histone H2B.

CONCLUSION

Our data provide evidence that autoantibodies targeting α-enolase, citrullinated fibrinogen, and citrullinated histone H2B are produced by the ongoing activated B cell response in, and thus may contribute to the pathogenesis of, RA.

High-throughput sequencing of natively paired antibody chains provides evidence for original antigenic sin shaping the antibody response to influenza vaccination

We developed a DNA barcoding method to enable high-throughput sequencing of the cognate heavy- and light-chain pairs of the antibodies expressed by individual B cells. We used this approach to elucidate the plasmablast antibody response to influenza vaccination. We show that >75% of the rationally selected plasmablast antibodies bind and neutralize influenza, and that antibodies from clonal families, defined by sharing both heavy-chain VJ and light-chain VJ sequence usage, do so most effectively. Vaccine-induced heavy-chain VJ regions contained on average >20 nucleotide mutations as compared to their predicted germline gene sequences, and some vaccine-induced antibodies exhibited higher binding affinities for hemagglutinins derived from prior years' seasonal influenza as compared to their affinities for the immunization strains. Our results show that influenza vaccination induces the recall of memory B cells that express antibodies that previously underwent affinity maturation against prior years' seasonal influenza, suggesting that 'original antigenic sin' shapes the antibody response to influenza vaccination.

Cutting edge: a TLR9 cytoplasmic tyrosine motif is selectively required for proinflammatory cytokine production

Compartmentalization of nucleic acid sensing TLR9 has been implicated as a mechanism to prevent recognition of self nucleic acid structures. Furthermore, recognition of CpG DNA in different endosomal compartments leads to the production of the proinflammatory cytokine TNF-α, or type I IFN. We previously characterized a tyrosine-based motif at aa 888-891 in the cytoplasmic tail of TLR9 important for appropriate intracellular localization. In this article, we show that this motif is selectively required for the production of TNF, but not IFN. In response to CpG DNA stimulation, the proteolytically processed 80-kDa fragment is tyrosine phosphorylated. Although Y888 is not itself phosphorylated, the structure of this motif is necessary for both TLR9 phosphorylation and TNF-α production in response to CpG DNA. We conclude that bifurcation in TLR9 signaling is regulated by a critical tyrosine motif in the cytoplasmic tail.

Early response of mucosal epithelial cells during Toxoplasma gondii infection

The innate immune response of mucosal epithelial cells during pathogen invasion plays a central role in immune regulation in the gut. Toxoplasma gondii is a protozoan intracellular parasite that is usually transmitted through oral infection. Although much of the information on immunity to T. gondii has come from i.p. infection models, more recent studies have revealed the importance of studying immunity following infection through the natural peroral route. Oral infection studies have identified many of the key players in the intestinal response; however, they have relied on responses detected days to weeks following infection. Much less is known about how the gut epithelial layer senses and reacts during initial contact with the pathogen. Given the importance of epithelial cells during pathogen invasion, this study uses an in vitro approach to isolate the key players and examine the early response of intestinal epithelial cells during infection by T. gondii. We show that human intestinal epithelial cells infected with T. gondii elicit rapid MAPK phosphorylation, NF-kappaB nuclear translocation, and secretion of IL-8. Both ERK1/2 activation and IL-8 secretion responses were shown to be MyD88 dependent and TLR2 was identified to be involved in the recognition of the parasite regardless of the parasite genotype. Furthermore, we were able to identify additional T. gondii-regulated genes in the infected cells using a pathway-focused array. Together, our findings suggest that intestinal epithelial cells were able to recognize T. gondii during infection, and the outcome is important for modulating intestinal immune responses.

Vibrio parahaemolyticus growth under low-iron conditions and survival under high-magnesium conditions

Since 1996, Vibrio parahaemolyticus serotype O3:K6 and closely related strains have been associated with an increased incidence of V. parahaemolyticus gastroenteritis worldwide, suggesting the emergence of strains with enhanced abilities to cause disease. One hypothesis for the recent emergence of V. parahaemolyticus O3:K6 and related strains is an enhanced capacity for environmental survival relative to other strains, which might result in increased human exposure to these organisms. Therefore, the objective of this study was to test the hypothesis that survival or growth characteristics of clinical V. parahaemolyticus isolates differ from those of nonclinical isolates under different environmental conditions. Twenty-six V. parahaemolyticus isolates selected to represent either clinical or food sources were monitored for either survival following exposure to high magnesium (300 mM) or growth under iron-limited conditions. Isolates in each category (clinical or food) differed widely in survival capabilities following 24 h of exposure to 300 mM Mg2+. Although 4 of 15 clinical isolates grew better at approximately 0.96 microM Fe2+ (iron-limited conditions) than at 50 microM Fe2+ (iron-rich conditions), as an entire group clinical isolates in this study were not more effective at growing under iron-limited conditions than were strains not associated with disease. Within the diverse collection of strains examined in these experiments, neither growth characteristics in low-iron environments nor survival capabilities following exposure to high magnesium concentrations were uniformly different between clinical and nonclinical V. parahaemolyticus isolates. Therefore, neither phenotypic characteristic can be used to reliably differentiate potentially pathogenic V. parahaemolyticus strains.

Cordyceps sinensis increases the expression of major histocompatibility complex class II antigens on human hepatoma cell line HA22T/VGH cells

Previous studies suggest that down-regulation of the major histocompatibility complex (MHC) antigens on the cell surface of certain tumors results in an escape of immune surveillance. Cordyceps sinensis is well known for its modulatory effect on host immune system. To investigate the modulatory effect of Cordyceps sinensis on MHC class II antigen expression on hepatoma cells, immunostaining with monoclonal antibody (MAb) L243, against the HLA DR region of MHC class II antigens on human hepatoma cell line HA22T/VGH was analyzed by using flow cytofluorimetry. The degree of fluorescence intensity on L243(+) cells was expressed as relative mean fluorescence intensity (RMFI). The extract of Cordyceps sinensis (VGH-CS-ME-82, 40 micrograms/ml) was found to increase the MHC class II antigen expression on HA22T/VGH cells with the percentage of L243(+) cells 40.2 +/- 2.5 and RMFI 6.6 +/- 0.4; whereas cells without treatment disclosed the percentage of L243(+) cells 17.2 +/- 1.4 and RMFI 5.4 +/- 0.3, respectively (p < 0.05). There was a dose-related increase in the degree of fluorescence intensity in terms of RMFI on VGH-CS-ME-82 induced cells. The RMFI in cells treated with IFN-gamma 0, 0.2 and 5 ng/ml were 5.4 +/- 0.3, 8.2 +/- 0.4, and 24.9 +/- 1.5, respectively; whereas the RMFI in cells co-incubated with VGH-CS-ME-82 (40 micrograms/ml) and IFN-gamma 0, 0.2 ng/ml and 5 ng/ml were 6.7 +/- 0.2 (p < 0.05), 9.2 +/- 0.9 (p < 0.1) and 29.5 +/- 1.2 (p < 0.005), respectively. We conclude that VGH-CS-ME-82, either alone or with IFN-gamma induction, increases the MHC class II antigen expression on hepatoma cell line HA22T/VGH, which will shed light into the present immunotherapy, and make the host immune surveillance more effective against tumor cells with down-regulated MHC class II antigen expression.