Case report of fatal immune-mediated myocarditis following treatment with davoceticept (ALPN-202), a PD-L1-dependent CD28 costimulator and dual PD-L1/CTLA-4 checkpoint inhibitor, in combination with pembrolizumab.

Engagement of programmed death-1 (PD-1) and cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) can interfere with the CD28 signaling requisite for T-cell activation. While immune checkpoint inhibitors (ICIs) can relieve this suppression, they are unable to drive CD28 costimulation that may mechanistically contribute to ICI resistance. Thus, CD28 costimulation in the context of checkpoint inhibition may activate immunosuppressed T-cells in the tumor microenvironment. Davoceticept (ALPN-202) is an Fc fusion of a CD80 variant immunoglobulin domain (vIgD) designed to mediate PD-L1-dependent CD28 costimulation while inhibiting the PD-L1 and CTLA-4 checkpoints. PD-L1-restriction of davoceticept's CD28 costimulatory activity may minimize systemic T-cell activation and avoid untoward systemic toxicities. At the same time, preclinical studies have suggested that treatment with davoceticept during PD-1 inhibition may enhance antitumor activity by upregulating PD-L1, potentially synergizing with davoceticept's PD-L1-dependent costimulatory mechanism. This report details two cases of fatal cardiac events following treatment with davoceticept in combination with pembrolizumab (anti-PD-1) in the phase 1 study, NEON-2. Both events occurred in females in their 60s; one with choroidal melanoma and prior immunotherapy, the other with ICI-naïve microsatellite stable colorectal cancer. The clinical courses were fulminant with symptom onset at 2 weeks, followed by rapid decline. Cardiac autopsy from one patient confirmed immune-related myocarditis, and immunosequencing revealed expansion of a single T-cell clone that was not present in the pretreatment tumor. These cases highlight the importance of understanding risk factors that may contribute to immune-related myocarditis and other severe immune-related adverse events when CD28 agonism is targeted in the context of checkpoint inhibition.NEON-2 (NCT04920383).

Phase I studies of davoceticept (ALPN-202), a PD-L1-dependent CD28 co-stimulator and dual PD-L1/CTLA-4 inhibitor, as monotherapy and in combination with pembrolizumab in advanced solid tumors (NEON-1 and NEON-2).

BACKGROUND: Davoceticept (ALPN-202) is an Fc fusion of a CD80 variant immunoglobulin domain designed to mediate programmed death-ligand 1 (PD-L1)-dependent CD28 co-stimulation while inhibiting the PD-L1 and cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) checkpoints. The safety and efficacy of davoceticept monotherapy and davoceticept and pembrolizumab combination therapy in adult patients with advanced solid tumors were explored in NEON-1 and NEON-2, respectively. METHODS: In NEON-1 (n=58), davoceticept 0.001-10 mg/kg was administered intravenous either once weekly (Q1W) or once every 3 weeks (Q3W). In NEON-2 (n=29), davoceticept was administered intravenously at 2 dose levels (0.1 or 0.3 mg/kg) Q1W or Q3W with pembrolizumab (400 mg once every 6 weeks). In both studies, primary endpoints included incidence of dose-limiting toxicities (DLT); type, incidence, and severity of adverse events (AEs) and laboratory abnormalities; and seriousness of AEs. Secondary endpoints included antitumor efficacy assessed using RECIST v1.1, pharmacokinetics, anti-drug antibodies, and pharmacodynamic biomarkers. RESULTS: The incidence of treatment-related AEs (TRAEs) and immune-related adverse events (irAEs) was 67% (39/58) and 36% (21/58) with davoceticept monotherapy, and 62% (18/29) and 31% (9/29) with davoceticept and pembrolizumab combination, respectively. The incidence of ≥grade (Gr)3 TRAEs and ≥Gr3 irAEs was 12% (7/58) and 5% (3/58) with davoceticept monotherapy, and 24% (7/29) and 10% (3/29) with davoceticept and pembrolizumab combination, respectively. One DLT of Gr3 immune-related gastritis occurred during davoceticept monotherapy 3 mg/kg Q3W. During davoceticept combination with pembrolizumab, two Gr5 cardiac DLTs occurred; one instance each of cardiogenic shock (0.3 mg/kg Q3W, choroidal melanoma metastatic to the liver) and immune-mediated myocarditis (0.1 mg/kg Q3W, microsatellite stable metastatic colorectal adenocarcinoma), prompting early termination of both studies. Across both studies, five patients with renal cell carcinoma (RCC) exhibited evidence of clinical benefit (two partial response, three stable disease). CONCLUSIONS: Davoceticept was generally well tolerated as monotherapy at intravenous doses up to 10 mg/kg. Evidence of clinical activity was observed with davoceticept monotherapy and davoceticept in combination with pembrolizumab, notably in RCC. However, two fatal cardiac events occurred with the combination of low-dose davoceticept and pembrolizumab. Future clinical investigation with davoceticept should not consider combination with programmed death-1-inhibitor anticancer mechanisms, until its safety profile is more fully elucidated. TRIAL REGISTRATION NUMBER: NEON-1 (NCT04186637) and NEON-2 (NCT04920383).

Assessing the Impact of Multilevel Comprehensive Programming on SNAP-Ed Participant Behaviors.

PURPOSE: To examine differences in dietary, physical activity, and food selection behaviors of Utah SNAP-Ed participants who had varied breadth of engagement with various components of multilevel programming. METHOD: SNAP-Ed participants received a survey approximately 1 year after participating in nutrition classes. The survey measured diet, physical activity, and food selection behaviors and breadth of engagement with components of SNAP-Ed programming. Components of programming included nutrition education for adults and youth, nudge programs in food pantries and corner stores, farmers' market booths, social marketing campaign materials, and social media platforms. Kruskal-Wallis tests assessed differences in behaviors between varying breadths of program engagement. RESULTS: Among the 124 respondents, certain dietary behaviors improved with increased breadth of program engagement including intake of vegetables, low-fat dairy, and lean protein. Food selection behaviors including using MyPlate and preparing healthy foods on a budget, also improved with increased engagement. Physical activity was not impacted by additional breadth of exposure. CONCLUSIONS AND IMPLICATIONS: Findings suggest that multilevel comprehensive programming may enhance the impact of SNAP-Ed education for certain behaviors. Additional research is warranted on the impact of SNAP-Ed multilevel programming on targeted behaviors and health outcomes.

A Multi-Site Analysis of the Prevalence of Food Insecurity in the United States, before and during the COVID-19 Pandemic.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic profoundly affected food systems including food security. Understanding how the COVID-19 pandemic impacted food security is important to provide support and identify long-term impacts and needs. OBJECTIVE: The National Food Access and COVID research Team (NFACT) was formed to assess food security over different US study sites throughout the pandemic, using common instruments and measurements. This study presents results from 18 study sites across 15 states and nationally over the first year of the COVID-19 pandemic. METHODS: A validated survey instrument was developed and implemented in whole or part through an online survey of adults across the sites throughout the first year of the pandemic, representing 22 separate surveys. Sampling methods for each study site were convenience, representative, or high-risk targeted. Food security was measured using the USDA 6-item module. Food security prevalence was analyzed using ANOVA by sampling method to assess statistically significant differences. RESULTS: Respondents (n = 27,168) indicate higher prevalence of food insecurity (low or very low food security) since the COVID-19 pandemic, compared with before the pandemic. In nearly all study sites, there is a higher prevalence of food insecurity among Black, Indigenous, and People of Color (BIPOC), households with children, and those with job disruptions. The findings demonstrate lingering food insecurity, with high prevalence over time in sites with repeat cross-sectional surveys. There are no statistically significant differences between convenience and representative surveys, but a statistically higher prevalence of food insecurity among high-risk compared with convenience surveys. CONCLUSIONS: This comprehensive study demonstrates a higher prevalence of food insecurity in the first year of the COVID-19 pandemic. These impacts were prevalent for certain demographic groups, and most pronounced for surveys targeting high-risk populations. Results especially document the continued high levels of food insecurity, as well as the variability in estimates due to the survey implementation method.

Immune-stimulating antibody conjugates elicit robust myeloid activation and durable antitumor immunity.

Innate pattern recognition receptor agonists, including Toll-like receptors (TLRs), alter the tumor microenvironment and prime adaptive antitumor immunity. However, TLR agonists present toxicities associated with widespread immune activation after systemic administration. To design a TLR-based therapeutic suitable for systemic delivery and capable of safely eliciting tumor-targeted responses, we developed immune-stimulating antibody conjugates (ISACs) comprising a TLR7/8 dual agonist conjugated to tumor-targeting antibodies. Systemically administered human epidermal growth factor receptor 2 (HER2)-targeted ISACs were well tolerated and triggered a localized immune response in the tumor microenvironment that resulted in tumor clearance and immunological memory. Mechanistically, ISACs required tumor antigen recognition, Fcγ-receptor-dependent phagocytosis and TLR-mediated activation to drive tumor killing by myeloid cells and subsequent T-cell-mediated antitumor immunity. ISAC-mediated immunological memory was not limited to the HER2 ISAC target antigen since ISAC-treated mice were protected from rechallenge with the HER2- parental tumor. These results provide a strong rationale for the clinical development of ISACs.

Nudging Urban Food Pantry Users in Utah Toward Healthier Choices.

Purpose. To evaluate the impact of a nudge program on food pantry clients' self-reported selection and use of healthy foods. Method. A convenience sample of clients of six urban food pantries in Utah were surveyed about their experience with the Thumbs Up for Healthy Choices nudge program. Chi-square tests were used to identify associations between demographic characteristics and self-reported program impact. Results. Ninety-four percent (n = 158) of respondents agreed that the program made it easier to make healthy choices. Sixty-five percent reported healthier diets since its implementation. Additionally, Hispanic respondents were more likely to report positive impacts than non-Hispanic respondents. Conclusions and Implications. Nudge programs are effective in increasing the selection of healthy foods among pantry clients in Utah. Impacts seemed to be particularly positive for Hispanic pantry users in Utah. Nutrition programs should consider implementing these low-cost strategies to improve dietary quality of pantry users.

Double Up Food Bucks Participation is Associated with Increased Fruit and Vegetable Consumption and Food Security Among Low-Income Adults.

OBJECTIVE: To evaluate the effect of the Utah Double Up Food Bucks (DUFB) program on fruit and vegetable (F&V) intake and food security status among Supplemental Nutrition Assistance Program (SNAP) recipients. METHODS: Data were collected in 2015, using a before-and-after study design. At the farmers' market, a convenience sample of SNAP recipients was recruited for a survey and a 4-week telephone follow-up survey. Differences between the 2 surveys in food security and F&V intake were tested using the Wilcoxon signed-rank test. RESULTS: Follow-up surveys were completed with 138 (40%) of the 339 baseline participants. Median F&V consumption increased from 2.82 times per day to 3.29 times per day (median, interquartile range 1.48-3.99 and 3.28-5.02, respectively, P = .002). The percentage of DUFB participants who were food secure increased by 15% (P = .001). CONCLUSIONS AND IMPLICATIONS: The present results add to the growing literature indicating farmers' market incentives are associated with increased F&V consumption and decreased food insecurity. Although more research is needed, farmers' market incentives may be an effective area of policy intervention.

A Novel, Fully Human Anti-fucosyl-GM1 Antibody Demonstrates Potent In Vitro and In Vivo Antitumor Activity in Preclinical Models of Small Cell Lung Cancer.

Purpose: The ganglioside fucosyl-GM1 (FucGM1) is a tumor-associated antigen expressed in a large percentage of human small cell lung cancer (SCLC) tumors, but absent in most normal adult tissues, making it a promising target in immuno-oncology. This study was undertaken to evaluate the preclinical efficacy of BMS-986012, a novel, nonfucosylated, fully human IgG1 antibody that binds specifically to FucGM1.Experimental Design: The antitumor activity of BMS-986012 was evaluated in in vitro assays using SCLC cells and in mouse xenograft and syngeneic tumor models, with and without chemotherapeutic agents and checkpoint inhibitors.Results: BMS-986012 showed a high binding affinity for FcγRIIIa (CD16), which resulted in enhanced antibody-dependent cellular cytotoxicity (ADCC) against FucGM1-expressing tumor cell lines. BMS-986012-mediated tumor cell killing was also observed in complement-dependent cytotoxicity (CDC) and antibody-dependent cellular phagocytosis (ADCP) assays. In several mouse SCLC models, BMS-986012 demonstrated efficacy and was well tolerated. In the DMS79 xenograft model, tumor regression was achieved with BMS-986012 doses of 0.3 mg/kg and greater; antitumor activity was enhanced when BMS-986012 was combined with standard-of-care cisplatin or etoposide. In a syngeneic model, tumors derived from a genetically engineered model of SCLC were treated with BMS-986012 or anti-FucGM1 with a mouse IgG2a Fc and their responses evaluated; when BMS-986012 was combined with anti-PD-1 or anti-CD137 antibody, therapeutic responses significantly improved.Conclusions: Single-agent BMS-986012 demonstrated robust antitumor activity, with the addition of chemotherapeutic or immunomodulatory agents further inhibiting SCLC growth in the same models. These preclinical data supported evaluation of BMS-986012 in a phase I clinical trial of patients with relapsed, refractory SCLC. Clin Cancer Res; 24(20); 5178-89. ©2018 AACR.

Who Eats School Breakfast? Parent Perceptions of School Breakfast in a State With Very Low Participation.

BACKGROUND: Having breakfast is correlated with health and academic benefits; yet, many children do not consume breakfast, and participation in the federal School Breakfast Program remains low. The purpose of this study was to examine parent perceptions of school breakfast and identify relationships between those who consume breakfast at school and those who do not. METHODS: A random sample of 100 schools, representing 29 school districts, across the state of Utah was selected to participate in the survey. Administrators were asked to distribute an online survey link to the parents of their school. Parents answered questions about their oldest kindergarten through 12th grade child. Qualitative and quantitative analyses were performed. RESULTS: A total of 488 parents completed the survey. In a multilevel model, child grade level, participation in free and reduced-price lunch, and perceive benefits to school breakfast were significantly related to eating breakfast at school. Some major themes from the qualitative analysis included no need for school breakfast, perception of regional values, and logistical issues. CONCLUSIONS: Parent perception of school meals is related to participation. This study identifies several areas of perception that could be address through parent education to increase school breakfast participation.

Understanding the Experiences of Low-Income Individuals Receiving Farmers' Market Incentives in the United States: A Qualitative Study.

OBJECTIVE: The objective of this study was to identify benefits and barriers to using a farmers' market (FM) incentive program among program participants. DESIGN: In qualitative semistructured interviews, participants were asked about their experiences with shopping at FM, using FM incentives, barriers to fruit and vegetable (F&V) intake, and changes in dietary intake. Interviews were recorded and transcribed. Inductive content analysis was used to code, categorize, and develop themes based on the transcriptions. SETTING: A FM in Northern Utah. SUBJECTS: A convenience sample of participants ( n = 14) completed a 45- to 60-minute interview after receiving FM incentives for an 8-week intervention period. RESULTS: FM incentives reduced barriers associated with shopping at FM such as cost and accessibility among program participants. Incentives provided participants with greater spending flexibility, allowing parents to provide children with F&V that previously did not fit into their food budget. Participants reported greater family and community involvement when shopping at FM. However, the limited hours and days of operation were factors that reduced the use of FM among participants, even when incentives were provided. CONCLUSIONS: The perceived benefits and barriers to shopping at FM and receiving FM incentives should be considered by future programmers and funding agencies.

Reducing Food Insecurity and Improving Fruit and Vegetable Intake Among Farmers' Market Incentive Program Participants.

OBJECTIVE: To determine whether participation in a farmers' market incentive pilot program had an impact on food security and fruit and vegetable (F&V) intake of participants. METHODS: Participants in the Supplemental Nutrition Assistance Program were eligible to receive a dollar-per-dollar match up to $10/wk in farmers' market incentives. The researchers used a pretest-posttest design to measure F&V intake and food security status of 54 adult participants before and after receiving farmers' market incentives. The 6-item Behavior Risk Factor Surveillance System questionnaire and US Household Food Security Survey Module were used to measure F&V intake and food security, respectively. Wilcoxon signed-rank test was used to compare scores of F&V intake. RESULTS: After receiving incentives, fewer individuals reported experiencing food insecurity-related behaviors. A significantly increased intake (P < .05) was found among selected vegetables. CONCLUSION AND IMPLICATIONS: Participation in a farmers' market incentive program was positively related to greater food security and intake of select vegetables among participants in the Supplemental Nutrition Assistance Program.

Intention to change nutrition-related behaviors in adult participants of a Supplemental Nutrition Assistance Program-Education.

OBJECTIVE: To determine whether participation in selected Supplemental Nutrition Assistance Program-Education (SNAP-Ed) lessons had an impact on the intent to improve nutrition-related behaviors of participants. METHODS: A quantitative study using a retrospective post-then-pre design to measure SNAP-Ed outcomes of 203 adult participants after selected nutrition lessons in 14 counties across the state of Utah. After the intervention participants completed a retrospective post-then-pre survey evaluating intent to improve nutrition behaviors related to the SNAP-Ed lessons. Wilcoxon signed rank test with Bonferroni correction and paired t test were used. RESULTS: Participants reported sometimes engaging in nutrition related behaviors before attending SNAP-Ed lessons and intent to usually engage in these behaviors after attending SNAP-Ed lessons. CONCLUSION AND IMPLICATIONS: This study demonstrated that participation in selected SNAP-Ed lessons was positively related to the intent of participants to improve nutrition-related behaviors.

Providing nutrition education to recently resettled refugees: piloting a collaborative model and evaluation methods.

Resettled refugees experience high levels of food insecurity because of low English proficiency, limited job skills, and lack of understanding of the United States food system. This study evaluated integrating Supplemental Nutrition Assistance Program Education (SNAP-Ed) into English as Second Language (ESL) classes taught at a worksite- training program for recently resettled refugees and the feasibility of using food purchase receipts. A convenience sample of resettled refugees participated in SNAP-Ed one hour for 12 weeks during ESL classes. Food purchase receipts were collected for purchases one week prior to, first three weeks, last three weeks, and one week after classes. Participants were from 17 countries and 50% completed 12 lessons. Fifty-nine participants turned in receipts and 93% used SNAP funds. By integrating SNAP-Ed into ESL classes at a worksite-training center a hard-to-reach eligible population was reached. Further validation is needed to use food purchase receipts.

In vitro characterization of the anti-PD-1 antibody nivolumab, BMS-936558, and in vivo toxicology in non-human primates.

The programmed death-1 (PD-1) receptor serves as an immunologic checkpoint, limiting bystander tissue damage and preventing the development of autoimmunity during inflammatory responses. PD-1 is expressed by activated T cells and downmodulates T-cell effector functions upon binding to its ligands, PD-L1 and PD-L2, on antigen-presenting cells. In patients with cancer, the expression of PD-1 on tumor-infiltrating lymphocytes and its interaction with the ligands on tumor and immune cells in the tumor microenvironment undermine antitumor immunity and support its rationale for PD-1 blockade in cancer immunotherapy. This report details the development and characterization of nivolumab, a fully human IgG4 (S228P) anti-PD-1 receptor-blocking monoclonal antibody. Nivolumab binds to PD-1 with high affinity and specificity, and effectively inhibits the interaction between PD-1 and its ligands. In vitro assays demonstrated the ability of nivolumab to potently enhance T-cell responses and cytokine production in the mixed lymphocyte reaction and superantigen or cytomegalovirus stimulation assays. No in vitro antibody-dependent cell-mediated or complement-dependent cytotoxicity was observed with the use of nivolumab and activated T cells as targets. Nivolumab treatment did not induce adverse immune-related events when given to cynomolgus macaques at high concentrations, independent of circulating anti-nivolumab antibodies where observed. These data provide a comprehensive preclinical characterization of nivolumab, for which antitumor activity and safety have been demonstrated in human clinical trials in various solid tumors.

Single versus combined lethal effects of three agricultural insecticides on larvae of the freshwater insect Chironomus dilutus.

Pesticides are currently regulated individually but are present in aquatic systems as mixtures of toxicants. In this study, the lethal effects of three agricultural insecticides--chlorpyrifos, imidacloprid and dimethoate--on Chironomus dilutus larvae were examined. Ninety-six-hour static bioassays were performed using single, binary, and ternary toxicant mixtures. The effects of the binary mixtures were investigated using the MIXTOX model to determine if the mixtures behaved additively, synergistically, or antagonistically. Dimethoate was much less toxic than chlorpyrifos or imidacloprid. Chlorpyrifos and dimethoate were not additive in mixture despite their common mode of action (MOA) and resulted in opposing effects (synergism and antagonism, respectively) when combined with imidacloprid. Synergism was observed in the ternary mixture. These results suggest that current mixture models based on MOA alone may not always be adequate in describing mixture effects, as in the current situation of mixtures with relatively few components. Other factors, such as water solubility, secondary MOA, and mechanisms of toxicity, should also be considered in future investigations of multichemical-mixture effects.

Developing an online certification program for nutrition education assistants.

OBJECTIVE: To develop an online certification program for nutrition education paraprofessionals to increase knowledge and confidence and to overcome training barriers of programming time and travel expenses. DESIGN: An online interactive certification course based on Supplemental Nutrition Assistance Program-Education and Expanded Food and Nutrition Education Program core competencies was delivered to employees of both programs. Traditional vs online training was compared. Course content validity was determined through expert review by registered dietitians. Parameters studied included increase of nutrition knowledge and teaching technique/ability, educator satisfaction, and programming costs related to training. SETTING: Utah State University Extension. PARTICIPANTS: Twenty-two Supplemental Nutrition Assistance Program-Education and Expanded Food and Nutrition Education Program educators in Utah. MAIN OUTCOME MEASURES: Knowledge and skills were measured using pre/posttest statistics. Participant satisfaction was measured with a survey. ANALYSIS: Paired t test; satisfaction survey. RESULTS: The change in paraprofessional knowledge score was statistically significant (P < .001). Forty percent of paraprofessionals strongly agreed and 60% agreed they were better prepared as nutrition educators because of the training. An estimated $16,000 was saved by providing the training online as compared to a face-to-face training. CONCLUSIONS AND IMPLICATIONS: This interactive online program is a cost-effective way to increase paraprofessional knowledge and job satisfaction.

A phase II, randomized, double-blind, placebo-controlled study evaluating the efficacy and safety of MDX-1100, a fully human anti-CXCL10 monoclonal antibody, in combination with methotrexate in patients with rheumatoid arthritis.

OBJECTIVE: CXCL10 (also known as interferon-γ-inducible 10-kd protein [IP-10]) is a chemokine that potentially plays a role in the immunopathogenesis of rheumatoid arthritis (RA). We undertook this phase II study to evaluate the efficacy and safety of MDX-1100, a fully human, anti-CXCL10 (anti-IP-10) monoclonal antibody, in RA patients whose disease responded inadequately to methotrexate (MTX). METHODS: Patients with active RA receiving stable doses of MTX (10-25 mg weekly) were randomized to receive intravenous doses of 10 mg/kg MDX-1100 (n = 35) or placebo (n = 35) every other week. The primary end point was the proportion of patients meeting the American College of Rheumatology 20% improvement criteria (achieving an ACR20 response) on day 85, and patients were followed up for safety to day 141. RESULTS: The ACR20 response rate was significantly higher among MDX-1100-treated patients than among placebo-treated patients (54% versus 17%; P = 0.0024). Statistically significant differences in the ACR20 response rate between treatments were observed starting on day 43 (P < 0.05). The ACR50 and ACR70 response rates on day 85 did not differ between the groups. Overall, 51.4% of MDX-1100-treated patients and 30.3% of placebo-treated patients experienced at least 1 adverse event (AE). No study drug-related serious AEs were reported. CONCLUSION: MDX-1100 was well tolerated and demonstrated clinical efficacy in RA patients whose disease responded inadequately to MTX. This is the first study to demonstrate clinical efficacy of a chemokine inhibitor in RA and supports the notion of a potential role of IP-10 in the immunopathogenesis of RA.

Strong Navajo marriages.

The purpose of this qualitative study, conducted in two Navajo Nation chapters, was to learn what makes Navajo marriages strong because no research has been done on this topic. Twenty-one Navajo couples (42 individuals) who felt they had strong marriages volunteered to participate in the study. Couples identified the following marital strengths: (1) maintain communication, (2) nurture your relationship, (3) learn about marriage, (4) be prepared for marriage, and (5) have a strong foundation.

The PucC protein of Rhodobacter capsulatus mitigates an inhibitory effect of light-harvesting 2 alpha and beta proteins on light-harvesting complex 1.

Rhodobacter capsulatus contains lhaA and pucC genes that have been implicated in light-harvesting complex 1 and 2 (LH1 and LH2) assembly. The proteins encoded by these genes, and homologues in other photosynthetic organisms, have been classified as the bacteriochlorophyll delivery (BCD) family of the major facilitator superfamily. A new BCD family phylogenetic tree reveals that several PucC, LhaA and Orf428-related sequences each form separate clusters, while plant and cyanobacterial homologues cluster more distantly. The PucC protein is encoded in the pucBACDE superoperon which also codes for LH2 alpha (PucA) and beta (PucB) proteins. PucC was previously shown to be necessary for formation of LH2. This article gives evidence indicating that PucC has a shepherding activity that keeps the homologous alpha and beta proteins of LH1 and LH2 apart, allowing LH1 to assemble properly. This shepherding function was indicated by a 62% reduction in LH1 levels in DeltaLHII strains carrying plasmids encoding pucBA along with a C-terminally truncated pucC gene. More severe reductions in LH1 were seen when the truncated pucC gene was co-expressed in the presence of C-terminal PucC::PhoA fusion proteins. It appears that interaction between truncated PucC::PhoA fusion proteins and the truncated PucC protein disrupts LH1 assembly, pointing towards a PucC dimeric or multimeric functional unit.