You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["HealthCareActivity", "InjuryOrPoisoning", "BodySubstance", "IntellectualProduct", "AnatomicalStructure", "SpatialConcept", "Chemical", "Bacterium", "MedicalDevice", "Organization", "BiomedicalOccupationOrDiscipline", "Finding", "BiologicFunction", "Virus", "ResearchActivity", "ClinicalAttribute", "PopulationGroup", "Eukaryote", "BodySystem", "Food", "ProfessionalOrOccupationalGroup"].

Please return the output as a JSON object of the format: {"Virus": ["HIV", ...], "Bacterium": ["MRSA", ...], "AnatomicalStructure": ["Lung", ...], "BodySystem": ["CNS", ...], "BodySubstance": ["Serum", ...], "Finding": ["Headache", ...], "InjuryOrPoisoning": ["Fracture", ...], "BiologicFunction": ["Death", ...], "HealthCareActivity": ["Biopsy", ...], "ResearchActivity": ["Clinical trial", ...], "MedicalDevice": ["Lenses", ...], "SpatialConcept": ["Camps", ...], "BiomedicalOccupationOrDiscipline": ["Forensic medicine", ...], "Organization": ["WHO", ...], "ProfessionalOrOccupationalGroup": ["Provider", ...], "PopulationGroup": ["Swimmers", ...], "Chemical": ["Gold", ...], "Food": ["Rice", ...], "IntellectualProduct": ["RPAM", ...], "ClinicalAttribute": ["Biomarker", ...], "Eukaryote": ["Dogs", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Polysaccharide - Specific Memory B Cells Predict Protection against Experimental Human Pneumococcal Carriage We have previously demonstrated that experimental pneumococcal carriage enhances immunity and protects healthy adults against carriage reacquisition after rechallenge with a homologous strain. To investigate the role of naturally acquired pneumococcal protein and polysaccharide (PS)- specific immunity in protection against carriage acquisition using a heterologous challenge model. We identified healthy volunteers that were naturally colonized with pneumococcus and, after clearance of their natural carriage episode, challenged them with a heterologous 6B strain. In another cohort of volunteers we assessed 6BPS - specific, PspA - specific, and PspC - specific IgG and IgA plasma and memory B-cell populations before and 7, 14, and 35 days after experimental pneumococcal inoculation. Heterologous challenge with 6B resulted in 50% carriage among volunteers with previous natural pneumococcal carriage. Protection from carriage was associated with a high number of circulating 6BPS IgG - secreting memory B cells at baseline. There were no associations between protection from carriage and baseline levels of 6BPS IgG in serum or nasal wash, PspA - specific, or PspC - specific memory B cells or plasma cells. In volunteers who did not develop carriage, the number of circulating 6BPS memory B cells decreased and the number of 6BPS plasma cells increased postinoculation. Our data indicate that naturally acquired PS - specific memory B cells, but not levels of circulating IgG at time of pneumococcal exposure, are associated with protection against carriage acquisition.
{"AnatomicalStructure": ["memory B-cell populations", "plasma cells", "plasma", "Memory B Cells", "colonized", "memory B cells"], "Bacterium": ["6B strain", "pneumococcus", "6B", "Pneumococcal", "pneumococcal"], "BiologicFunction": ["heterologous challenge", "secreting", "Heterologous challenge", "immunity"], "BiomedicalOccupationOrDiscipline": [], "BodySubstance": ["serum", "nasal wash"], "BodySystem": [], "Chemical": ["IgG", "PspC", "PspA", "IgA", "pneumococcal protein", "Polysaccharide", "polysaccharide", "6BPS", "PS"], "ClinicalAttribute": [], "Eukaryote": ["Human"], "Finding": ["postinoculation", "not levels", "Carriage", "not develop", "carriage"], "Food": [], "HealthCareActivity": ["rechallenge", "inoculation"], "InjuryOrPoisoning": [], "IntellectualProduct": [], "MedicalDevice": [], "Organization": [], "PopulationGroup": ["volunteers", "healthy volunteers", "cohort"], "ProfessionalOrOccupationalGroup": [], "ResearchActivity": [], "SpatialConcept": [], "Virus": []}