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The purpose of this study was to examine effective design elements for online courses in the science, technology, engineering, and mathematics (STEM) fields at a large four-year public university in southeastern United States. Our research questions addressed the influence of online design elements on students' perception of learning and learning satisfaction. An online survey was completed by 537 students from 15 online STEM courses in spring 2016. The survey results indicated that student perceptions of learning and satisfaction were correlated with their perceptions of the efficacy of specific design elements, such as integrated active learning activities, interactive engagement strategies, and robust assessment design. In particular, perception of assessment design efficacy was significantly correlated with students' self-perceived learning and learning satisfaction for students of all subpopulations. The findings inform instructors and instructional designers on how to design effective, inclusive, and engaging online STEM courses. Student survey responses were observed to support universal design for learning (UDL) and in light of this, online STEM instructors are also strongly encouraged to utilize UDL principles in course design, which benefit not only students with disabilities but all students.

Despite the pressure from potential employers and higher education administrators to develop students' global and intercultural competence, traditional study abroad programs simply are not feasible for many postsecondary students (Berdan & Johannes, 2014; Fischer, 2015). The purpose of this study was to evaluate the effectiveness of an online delivery model for study abroad activities. Building upon the findings of an initial exploratory program using Adobe Connect web conferencing tools, this evaluative case study was the second in a series of design based research studies intended to identify effective practices and develop recommendations to further refine the model through an iterative evaluation process. Using the Online Learning Consortium's Quality Framework, each of the Five Pillars that support successful online learning (access, student satisfaction, faculty satisfaction, learning effectiveness, & scale) was evaluated through a combination of anonymous surveys, pre/post assessments, observations, and student & instructor interviews (Moore, 2005). Regarding access, 26 students who were enrolled in an intercultural communication course were able to participate in a study abroad experience in Italy; 10 students participated in the traditional study abroad trip in Italy while the other 16 participated virtually. The online students were able to join the live meetings, thus expanding their access to international experiences that normally would be closed to them. In terms of student and faculty satisfaction, both groups of students and the instructor reported specific areas of satisfaction, offered critical feedback, and felt that the concept was a viable one. While the students who traveled to Italy had a far more immersive experience, both groups demonstrated gains in learning. Using Morais and Ogden's (2010) global citizenship pre/post assessment, both groups showed improvement on the selfawareness and intercultural communication scales, and when comparing the two groups the online students improved more on the social responsibility scale while the students who traveled improved more on the global knowledge scale. Both groups submitted assignments of similar quality, engaged in communications between the abroad and online groups, and interacted with the instructor and experts in the field. In terms of differences in student engagement, students had differing opinions on the interaction with the technology and the online group asked more questions during live meetings. The implications of this pilot study should inform the planning of the next case evaluation and are important for other educators who wish to implement a similar approach to internationalizing the curriculum through online instruction.

Fostering metacognition can be challenging within large enrollment settings, particularly within STEM fields concentrating on problem-solving skills and their underlying theories. Herein, the research problem of realizing more frequent, insightful, and explicitly-rewarded metacognition activities at significant scale is investigated via a strategy utilizing a hierarchy of assessments. Referred to as the "STEM-Optimal Digitized Assessment Strategy (SODAS)," this targeted approach engages frequent assessment, instructor feedback, and learner self-reflection across the hierarchy of learning mechanisms comprising Bloom's Taxonomy of Learning Domains. SODAS spans this hierarchy of learning mechanisms via a progression of (i) unregulated online assessment, (ii) proctored Computer-Based Assessment (CBA), (iii) problem-based learning activities assessed in the laboratory setting, and (iv) personalized Socratic discussions of scanned scrap sheets that accompanied each learner's machine-graded formative assessments. Results of a case study integrating SODAS within a high-enrollment Mechanical Engineering Heat Transfer course at a large state university are presented for enrollment of 118 students. Six question types were delivered with lockdown proctored testing via auto-grading within the Canvas Learning Management System (LMS), along with bi-weekly laboratory activities to address the higher layers of Bloom's Taxonomy. Sample assessment formats were validated through student use and schedules of responsibilities for instructors across four tiers of assessment levels (facts, concepts, procedures, and metacognition), two testing delivery mechanisms (electronic textbook exercises and proctored CBA), and three remediation mechanisms (self-paced, score clarification, and experiment clarification), which showed that learning achievement can increase by up to 16.9% compared to conventional assessment strategies, while utilizing comparable instructor resources and workloads.

The Teaching Online Preparation Toolkit (TOPkit) is an open educational resource (website and two free, customizable online faculty development courses) that faculty developers anywhere can use. Florida-funded and Florida-focused in support of the State University System of Florida Board of Governors 2025 Strategic Plan for Online Education, TOPkit is a comprehensive resource that provides instructional designers, faculty developers, and educational technologists with the essential tools required to support faculty in the development of high-quality online courses. This article describes the online toolkit and specifically highlights the toolkit's pair of sample courses that may be downloaded and customized.

During the 1918 influenza pandemic, the virus likely passed from humans to pigs (1). Descendants of this virus (classical swine influenza viruses), first isolated in 1930 (2), have continued to [...]

Hybrid online delivery, which is also referred to as mixed-mode delivery, utilizes a combination of online content and traditional face-to-face methods which may benefit significantly from specific delivery adaptations for undergraduate engineering curricula. Herein, a novel eight-step phased instructional flow with several targeted adaptations is used to accommodate the mixed-mode delivery of STEM curricula is evaluated with a longitudinal study of students afforded these adaptations versus those without them. This STEM Blended Delivery Protocol (STEM-BDP) emphasizes scaffolding of analytical procedures along with hands-on problem solving throughout online and face-to-face components equally. Two high enrollment course case studies utilizing STEM-BDP are examined herein, including an Electrical and Computer Engineering required core undergraduate course and a Mechanical and Aerospace Engineering undergraduate course. The details of the STEM-BDP delivery strategies, learning activities, and student perceptions surveys are presented. Student-resolution longitudinal analysis within a controlled study using blinded evaluation indicates that over a five-year period, failure rates have decreased by 63% among students undergoing STEM-BDP while control and alternatives have not demonstrated similar improvements within the same degree programs. Given increasing enrollments within STEM curricula, it is sought to overcome challenges of conventional lecture-only delivery in high-enrollment courses. [ABSTRACT FROM AUTHOR]

Background: The burden of depressive disorder is large and new treatment approaches are required. Repurposing widely available drugs such as statins may be a time- and cost-effective solution. Statins have anti-inflammatory and anti-oxidant properties which have been shown to be relevant to the pathophysiology of depression. This study assesses the efficacy, acceptability, tolerability, and safety of statins in major depressive disorder. Methods: Our study is an update and extension of a previous meta-analysis published in 2016 by Salagre et al. We performed a systematic review (PubMed/MEDLINE, Cochrane CENTRAL, ISI Web of Science, CINAHL, and ClinicalTrials.gov until the 1st September 2020) and meta-analysis of randomized controlled trials using any statin against placebo or any other statin in the treatment of major depressive disorder. Our primary efficacy outcome measure was the mean value on any standardized scale for depressive symptoms at 8 weeks of treatment. We also calculated outcomes for efficacy, response, and remission at 2, 4, and 12 weeks, as well as acceptability (dropouts for any cause), tolerability (dropouts due to any adverse event), and safety (any adverse event) outcomes at the studies' endpoints. Furthermore, we conducted an exploratory network meta-analysis for the primary efficacy outcome to identify potential differences between statins. Results: We retrieved five randomized controlled trials meeting our inclusion criteria: four used a statin in addition to an antidepressant and compared it to placebo plus antidepressant, and one compared two statins alone. and one comparing one statin with another. Statins compared to placebo in addition to antidepressants were efficacious at 8 weeks (N = 255, SMD = -0.48, 95% CI = -0.74 to -0. 22) and 12 weeks (N = 134, SMD = -0.47, 95% CI = -0.89 to -0.05, moderate certainty) with no difference for acceptability, tolerability, and safety (low certainty). An exploratory network meta-analysis suggested that the most lipophilic statins, especially simvastatin, could be more efficacious than less lipophilic or hydrophilic molecules. Conclusions: This systematic review suggests the efficacy, acceptability, tolerability, and safety of statins in addition to antidepressants in patients with major depressive disorder. Further clinical trials in different settings are required to test this result. Trial rgistration: PROSPERO registration: CRD42020170938. [ABSTRACT FROM AUTHOR]

The purpose of this study was to examine effective design elements for online courses in the science, technology, engineering, and mathematics (STEM) fields at a large four-year public university in southeastern United States. Our research questions addressed the influence of online design elements on students' perception of learning and learning satisfaction. An online survey was completed by 537 students from 15 online STEM courses in spring 2016. The survey results indicated that student perceptions of learning and satisfaction were correlated with their perceptions of the efficacy of specific design elements, such as integrated active learning activities, interactive engagement strategies, and robust assessment design. In particular, perception of assessment design efficacy was significantly correlated with students' self-perceived learning and learning satisfaction for students of all subpopulations. The findings inform instructors and instructional designers on how to design effective, inclusive, and engaging online STEM courses. Student survey responses were observed to support universal design for learning (UDL) and in light of this, online STEM instructors are also strongly encouraged to utilize UDL principles in course design, which benefit not only students with disabilities but all students. [ABSTRACT FROM AUTHOR]

The article reviews The Teaching Online Preparation Toolkit located at TOPkit.org.

Despite the pressure from potential employers and higher education administrators to develop students' global and intercultural competence, traditional study abroad programs simply are not feasible for many postsecondary students (Berdan & Johannes, 2014; Fischer, 2015). The purpose of this study was to evaluate the effectiveness of an online delivery model for study abroad activities. Building upon the findings of an initial exploratory program using Adobe Connect web conferencing tools, this evaluative case study was the second in a series of design based research studies intended to identify effective practices and develop recommendations to further refine the model through an iterative evaluation process. Using the Online Learning Consortium's Quality Framework, each of the Five Pillars that support successful online learning (access, student satisfaction, faculty satisfaction, learning effectiveness, & scale) was evaluated through a combination of anonymous surveys, pre/post assessments, observations, and student & instructor interviews (Moore, 2005). Regarding access, 26 students who were enrolled in an intercultural communication course were able to participate in a study abroad experience in Italy; 10 students participated in the traditional study abroad trip in Italy while the other 16 participated virtually. The online students were able to join the live meetings, thus expanding their access to international experiences that normally would be closed to them. In terms of student and faculty satisfaction, both groups of students and the instructor reported specific areas of satisfaction, offered critical feedback, and felt that the concept was a viable one. While the students who traveled to Italy had a far more immersive experience, both groups demonstrated gains in learning. Using Morais and Ogden's (2010) global citizenship pre/post assessment, both groups showed improvement on the selfawareness and intercultural communication scales, and when comparing the two groups the online students improved more on the social responsibility scale while the students who traveled improved more on the global knowledge scale. Both groups submitted assignments of similar quality, engaged in communications between the abroad and online groups, and interacted with the instructor and experts in the field. In terms of differences in student engagement, students had differing opinions on the interaction with the technology and the online group asked more questions during live meetings. The implications of this pilot study should inform the planning of the next case evaluation and are important for other educators who wish to implement a similar approach to internationalizing the curriculum through online instruction. [ABSTRACT FROM AUTHOR]

There are substantial quantitative research and anecdotal reports on blended learning and blended learning courses. However, few research studies focus on what happens at the classroom level. This research study aims to consider the highly contextual environment of effective blended learning courses by identifying the strategies instructors use to unify the face-to-face and online components of their courses to support student success. Using a case study model, interviews were conducted with three community college instructors who were identified as exemplary teachers of blended learning courses in their institutions. The research questions explored in this article are: (R1) What are exemplary community college teachers' perceived obstacles to student success in blended courses? and (R2) What solutions or strategies do exemplary community college teachers employ to overcome perceived obstacles to student success in blended courses? The interviews were analyzed by the researchers to identify descriptive themes and sub-themes related to student success. It was found that "comfort" emerged as a mediating factor for student success, with "organization," "communication," and "support" acting as supporting themes. These findings will be reported as pedagogical strategies and scalable best practices for the design of blended courses that promote student success. [ABSTRACT FROM AUTHOR]

Clade 2.2 Eurasian-lineage H5N1 highly pathogenic avian influenza viruses (HPAIVs) were first detected in Qinghai Lake, China, in 2005 and subsequently spread through Asia, Europe, and Africa. Importantly, these viruses carried a lysine at amino acid position 627 of the PB2 protein (PB2 627K), a known mammalian adaptation motif. Previous avian influenza virus isolates have carried glutamic acid in this position (PB2 627E), commonly described to restrict virus polymerase function in the mammalian host. We sought to examine the effect of PB2 627K on viral maintenance in the avian reservoir. Viruses constructed by reverse genetics were engineered to contain converse PB2 627K/E mutations in a Eurasian H5N1 virus (A/turkey/Turkey/5/2005 [Ty/05]) and, for comparison, a historical pre-Asian H5N1 HPAIV that naturally bears PB2 627E (A/turkey/England/50-92/1991 [50-92]). The 50-92 PB2 627K was genetically unstable during virus propagation, resulting in reversion to PB2 627E or the accumulation of the additional mutation PB2 628R and/or a synonymous mutation from an A to a G nucleotide at nucleotide position 1869 (PB2 A1869G). Intriguingly, PB2 628R and/or A1869G appeared to improve the genetic stability of 50-92 PB2 627K. However, the replication of 50-92 PB2 627K in conjunction with these stabilizing mutations was significantly restricted in experimentally infected chickens, where reversion to PB2 627E occurred. In contrast, no significant effects on viral fitness were observed for Ty/05 PB2 627E or 627K in in vitro or in vivo experiments. Our observations suggest that PB2 627K is supported in Eurasianlineage viruses; in contrast, PB2 627K carries a significant fitness cost in the historical pre-Asian 50-92 virus. [ABSTRACT FROM AUTHOR]

Young patients with myasthenia gravis (MG) frequently have ectopic GC in their thymus. We investigated these ectopic GC by microdissection of GC B cells and analysis of their Ig gene characteristics, in comparison to normal GC. CDR3 length distribution, a measure of clonal variability, and Ig gene family usage were similar in MG and normal tonsil samples. Lineage tree analysis demonstrated similar diversification and mutations per cell compared with normal control trees. Mutations were observed in the framework regions, responsible for the structural integrity of the BCR; however, these mutations were mostly conservative or neutral, confirming that a functional BCR is conserved in MG. In the CDR, responsible for Ag binding, selection against replacement mutations was revealed. This may indicate that the MG clones analyzed are already highly Ag-specific, and therefore potential affinity-reducing replacement mutations in the CDR3 are not propagated, due to Ag-driven selection. Somatic hypermutation (SHM) targeting motifs and aa substitution preferences in MG were similar to those of normal controls. Overall, these results suggest that B cells in the ectopic GC in MG appear to undergo normal diversification and selection, in spite of the chronic nature and different environment of the response. [ABSTRACT FROM AUTHOR]

Abstract: Influenza vaccines are potentially the most efficacious means of mitigating the impact of influenza pandemic and might contribute to the rapid containment of an emerging pandemic virus. On the 12–13 February 2009, the Initiative For Vaccine Research (IVR) of the World Health Organisation convened the 5th meeting on the ‘Evaluation of pandemic influenza prototype vaccines in clinical trials’ in Geneva. This was a follow-up meeting to the 4th meeting held on 14–15 February 2008 [Girard M, Palkonyay L, Kieny MP. Report of the 4th meeting on the evaluation of pandemic influenza prototype vaccines in clinical trials. Vaccine 2008;26:4975–7], and presentations were made by representatives from industry, academia, and governmental organisations. This year''s meeting aimed to update the progress made during the past year on H5N1 and other prototype pandemic vaccines that have undergone clinical trials. A number of vaccine types were covered, including classical egg-derived inactivated vaccines, cell-derived inactivated vaccines, live-attenuated vaccines (LAIV) and vaccines developed using new technologies. The effects of different adjuvants and prime-boosting schedules were important topics, and further data were presented to show that children mount vigorous antibody responses to several H5N1 vaccines. Other subjects presented and discussed were standardisation, and regulatory issues concerning pandemic vaccines. [Copyright &y& Elsevier]

Outbreaks of highly pathogenic avian influenza virus (HPAIV) often result in the infection of millions of poultry, causing up to 100% mortality. HPAIV has been shown to emerge from low pathogenicity avian influenza virus (LPAIV) in field outbreaks. Direct evidence for the emergence of H7N7 HPAIV from a LPAIV precursor with a rare di-basic cleavage site (DBCS) was identified in the UK in 2008. The DBCS contained an additional basic amino acid compared to commonly circulating LPAIVs that harbor a single-basic amino acid at the cleavage site (SBCS). Using reverse genetics, outbreak HPAIVs were rescued with a DBCS (H7N7DB), as seen in the LPAIV precursor or an SBCS representative of common H7 LPAIVs (H7N7SB). Passage of H7N7DB in chicken embryo tissues showed spontaneous evolution to a HPAIV. In contrast, deep sequencing of extracts from embryo tissues in which H7N7SB was serially passaged showed retention of the LPAIV genotype. Thus, in chicken embryos, an H7N7 virus containing a DBCS appears naturally unstable, enabling rapid evolution to HPAIV. Evaluation in embryo tissue presents a useful approach to study AIV evolution and allows a laboratory-based dissection of molecular mechanisms behind the emergence of HPAIV. [ABSTRACT FROM AUTHOR]

Abstract: Current influenza vaccines are limited by the need for annual immunisation, frequent antigenic updating to match the evolution of circulating influenza virus strains, and reduced efficacy in elderly persons. On 9–10 November 2009, the Initiative for Vaccine Research of the World Health Organization convened jointly with the Wellcome Trust in London, United Kingdom, the fourth meeting on ‘Influenza vaccines that induce broad spectrum and long-lasting immune responses’. Presentations were made by representatives from industry, academia, governmental and non-governmental organisations. The objectives of the meeting were to update the progress of research in the field of influenza vaccine strategies able to generate cross protection against divergent influenza virus strains. Improvements in existing strategies including live attenuated influenza vaccines and adjuvantation of inactivated vaccines were summarised. Developments in novel antigen production methods, new routes of vaccine delivery and administration, and vaccine approaches based on conserved virus antigens were explored. In addition, correlates of immune protection and regulatory issues for the evaluation and approval of future novel vaccine strategies were discussed. [Copyright &y& Elsevier]

Influenza A virus segment 2 is known to encode two polypeptides in overlapping open reading frames: PB1, the polymerase, and PB1-F2, a proapoptotic virulence factor. We show that a third major polypeptide is synthesized from PB1 mRNA via differential AUG codon usage. PB1 codon 40 directs translation of an N-terminally truncated version of the polypeptide (N40) that lacks transcriptase function but nevertheless interacts with PB2 and the polymerase complex in the cellular environment. Importantly, the expression of N40, PB1-F2, and PB1 are interdependent, and certain mutations previously used to ablate PB1-F2 production affected N40 accumulation. Removal of the PB1-F2 AUG upregulated N40 synthesis, while truncating PB1-F2 after codon 8 (with a concomitant M40I change in PB1) abolished N40 expression. A virus lacking both N40 and PB1-F2 replicated normally. However, viruses that did not express N40 but retained an intact PB1-F2 gene overexpressed PB1 early in infection and replicated slowly in tissue culture. Thus, the influenza A virus proteome includes a 12th primary translation product that (similarly to PB1-F2) is nonessential for virus viability but whose loss, in particular genetic backgrounds, is detrimental to virus replication. [ABSTRACT FROM AUTHOR]

Highly pathogenic H5N1 avian influenza viruses cause devastating outbreaks in farmed poultry with serious consequences for animal welfare and economic losses. Zoonotic infection of humans through close contact with H5N1 infected birds is often severe and fatal. England experienced an outbreak of H5N1 in turkeys in 1991 that led to thousands of farmed bird mortalities. Isolation of clonal populations of one such virus from this outbreak uncovered amino acid differences in the virus haemagglutinin (HA) gene whereby the different genotypes could be associated with distinct pathogenic outcomes in chickens; both low pathogenic (LP) and high pathogenic (HP) phenotypes could be observed despite all containing a multi-basic cleavage site (MBCS) in the HA gene. Using reverse genetics, three amino acid substitutions in HA were examined for their ability to affect pathogenesis in the chicken. Restoration of amino acid polymorphisms close to the receptor binding site that are commonly found in H5 viruses only partially improved viral fitness in vitro and in vivo . A third novel substitution in the fusion peptide, HA 2 G4R, enabled the HP phenotype. HA 2 G4R decreased the pH stability of HA and increased the pH of HA fusion. The substitutions close to the receptor binding site optimised receptor binding while modulating the pH of HA fusion. Importantly, this study revealed pathogenic determinants beyond the MBCS.

Avian influenza is a significant economic burden on the poultry industry in geographical regions where it is enzootic. It also poses a public health concern when avian influenza subtypes infect humans, often with high mortality. Understanding viral genetic factors which positively contribute to influenza A virus (IAV) fitness - infectivity, spread and pathogenesis - is of great importance both for human and livestock health. PB1-F2 is a small accessory protein encoded by IAV and in mammalian hosts has been implicated in a wide range of functions that contribute to increased pathogenesis. In the avian host, the protein has been understudied despite high-level full-length conservation in avian IAV isolates, which is in contrast to the truncations of the PB1-F2 length frequently found in mammalian host isolates. Here we report that the presence of a full-length PB1-F2 protein, from a low pathogenicity H9N2 avian influenza virus, prolongs infectious virus shedding from directly inoculated chickens, thereby enhancing transmission of the virus by lengthening the transmission window to contact birds. As well as extending transmission, the presence of a full-length PB1-F2 suppresses pathogenicity evidenced by an increased minimum lethal dose in embryonated chicken eggs and increasing survival in directly infected birds when compared to a virus lacking an ORF for PB1-F2. We propose that there is a positive pressure to maintain a full-length functional PB1-F2 protein upon infection of avian hosts as it contributes to the effective transmission of IAV in the field.

Unlabelled: Skeletal muscle, at 30 to 40% of body mass, is the most abundant soft tissue in the body. Besides its primary function in movement and posture, skeletal muscle is a significant innate immune organ with the capacity to produce cytokines and chemokines and respond to proinflammatory cytokines. Little is known about the role of skeletal muscle during systemic influenza A virus infection in any host and particularly avian species. Here we used primary chicken and duck multinucleated myotubes to examine their susceptibility and innate immune response to influenza virus infections. Both chicken and duck myotubes expressed avian and human sialic acid receptors and were readily susceptible to low-pathogenicity (H2N3 A/mallard duck/England/7277/06) and high-pathogenicity (H5N1 A/turkey/England/50-92/91 and H5N1 A/turkey/Turkey/1/05) avian and human H1N1 (A/USSR/77) influenza viruses. Both avian host species produced comparable levels of progeny H5N1 A/turkey/Turkey/1/05 virus. Notably, the rapid accumulation of viral nucleoprotein and matrix (M) gene RNA in chicken and duck myotubes was accompanied by extensive cytopathic damage with marked myotube apoptosis (widespread microscopic blebs, caspase 3/7 activation, and annexin V binding at the plasma membrane). Infected chicken myotubes produced significantly higher levels of proinflammatory cytokines than did the corresponding duck cells. Additionally, in chicken myotubes infected with H5N1 viruses, the induction of interferon beta (IFN-β) and IFN-inducible genes, including the melanoma differentiation-associated protein 5 (MDA-5) gene, was relatively weak compared to infection with the corresponding H2N3 virus. Our findings highlight that avian skeletal muscle fibers are capable of productive influenza virus replication and are a potential tissue source of infection., Importance: Infection with high-pathogenicity H5N1 viruses in ducks is often asymptomatic, and skeletal muscle from such birds could be a source of infection of humans and animals. Little is known about the ability of influenza A viruses to replicate in avian skeletal muscle fibers. We show here that cultured chicken and duck myotubes were highly susceptible to infection with both low- and high-pathogenicity avian influenza viruses. Infected myotubes of both avian species displayed rapid virus accumulation, apoptosis, and extensive cellular damage. Our results indicate that avian skeletal muscle fibers of chicken and duck could be significant contributors to progeny production of highly pathogenic H5N1 viruses., (Copyright © 2015, Baquero-Perez et al.)

Vaccination of mice with the 42-kDa region of Plasmodium yoelii merozoite surface protein 1 (MSP1(42)) or its 19-kDa C-terminal processing product (MSP1(19)) can elicit protective antibody responses in mice. To investigate if the 33-kDa N-terminal fragment (MSP1(33)) of MSP1(42) also induces protection, the gene segment encoding MSP1(33) was expressed as a glutathione S-transferase (GST) fusion protein. C57BL/6 and BALB/c mice were immunized with GST-MSP1(33) and subsequently challenged with the lethal P. yoelii YM blood stage parasite. GST-MSP1(33) failed to induce protection, and all mice developed patent parasitemia at a level similar to that in naive or control (GST-immunized) mice; mice immunized with GST-MSP1(19) were protected, as has been shown previously. Specific prechallenge immunoglobulin G (IgG) antibody responses to MSP1 were analyzed by enzyme-linked immunosorbent assay and immunofluorescence. Despite being unprotected, several mice immunized with MSP1(33) had antibody titers (of all IgG subclasses) that were comparable to or higher than those in mice that were protected following immunization with MSP1(19). The finding that P. yoelii MSP1(33) elicits strong but nonprotective antibody responses may have implications for the design of vaccines for humans based on Plasmodium falciparum or Plasmodium vivax MSP1(42).