Natural allergens MCQs With Answer

Introduction: Natural allergens MCQs With Answer provides B. Pharm students a focused, practical review of common environmental and food allergens, their immunological mechanisms, diagnostic tests, and pharmaceutical management. This resource emphasizes keywords such as natural allergens, IgE-mediated hypersensitivity, pollen, dust mite, mold, food allergens, cross-reactivity, component-resolved diagnostics, allergen extracts, standardization, immunotherapy, and pharmacotherapy. Questions target extraction and formulation of allergen vaccines, stability and preservatives, mechanisms of desensitization, and emergency treatment of anaphylaxis. Designed to strengthen clinical pharmaceutics and immunology knowledge, the MCQs combine conceptual depth with applied pharmacy relevance. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. What defines a ‘natural allergen’ in the context of allergy diagnostics?

• Any synthetic peptide used in vaccines
• Chemical irritants causing non-immune reactions
• Biological substances from nature that can induce IgE-mediated reactions
• Only food-derived proteins

Correct Answer: Biological substances from nature that can induce IgE-mediated reactions

Q2. Which term describes an allergen recognized by IgE in most sensitized individuals (induces strong responses)?

• Minor allergen
• Major allergen
• Hapten
• Adjuvant

Correct Answer: Major allergen

Q3. Der p 1 is a major allergen derived from which source?

• Bee venom
• House dust mite
• Grass pollen
• Soybean

Correct Answer: House dust mite

Q4. Bet v 1 is the major allergen from which pollen source?

• Ragweed
• Birch
• Grass
• Olive

Correct Answer: Birch

Q5. Tropomyosin is a pan-allergen commonly responsible for cross-reactivity between:

• Penicillins and cephalosporins
• Shellfish and dust mites
• Milk and egg white
• Pollen and nickel

Correct Answer: Shellfish and dust mites

Q6. Cross-reactive carbohydrate determinants (CCDs) in natural allergens mainly cause which laboratory issue?

• False-negative skin prick tests
• False-positive specific IgE results due to non-protein IgE binding
• Complete degradation of allergen extracts
• Increased potency of immunotherapy

Correct Answer: False-positive specific IgE results due to non-protein IgE binding

Q7. Component-resolved diagnostics (CRD) in allergy testing refers to:

• Measuring total IgE only
• Using whole-extract tests exclusively
• Detecting IgE to individual allergenic proteins or molecular components
• Culture-based identification of allergens

Correct Answer: Detecting IgE to individual allergenic proteins or molecular components

Q8. The principle of the skin prick test relies primarily on which immunologic mechanism?

• IgG-mediated complement activation
• IgE binding to mast cells causing immediate degranulation
• T-cell delayed hypersensitivity
• Direct neutrophil cytotoxicity

Correct Answer: IgE binding to mast cells causing immediate degranulation

Q9. ImmunoCAP and RAST tests measure which parameter in patient serum?

• Specific IgA to allergens
• Specific IgE to allergens
• T-cell proliferation to allergens
• Total leukocyte count

Correct Answer: Specific IgE to allergens

Q10. Immediate (Type I) hypersensitivity is characterized by which sequence?

• Antigen — IgG — complement — cytotoxicity
• Antigen — IgE — mast cell degranulation — histamine release
• Antigen — T-cell activation — granuloma formation
• Antigen — immune complex deposition — vasculitis

Correct Answer: Antigen — IgE — mast cell degranulation — histamine release

Q11. Which mediator is primarily responsible for increased vascular permeability and wheal formation in allergy?

• Histamine
• TNF-alpha only
• Interferon-gamma
• Insulin

Correct Answer: Histamine

Q12. Which cytokines are classically associated with Th2 responses in allergic disease?

• IL-2 and IFN-gamma
• IL-4, IL-5 and IL-13
• IL-17 and IL-23
• TNF-alpha and IL-1

Correct Answer: IL-4, IL-5 and IL-13

Q13. Eosinophil recruitment and activation in allergies is principally driven by which interleukin?

• IL-1
• IL-5
• IL-10
• IL-12

Correct Answer: IL-5

Q14. Which unit is commonly used for expressing potency of standardized allergen extracts?

• IU for vaccines only
• BAU or AU (biological activity units)
• mg/dL of protein
• CFU per mL

Correct Answer: BAU or AU (biological activity units)

Q15. Which excipient is commonly added to allergen extracts to enhance stability during storage?

• Ethanol 95% as sole solvent
• Glycerol or phenol-containing buffers
• Sodium azide at high concentration for long-term use in humans
• Live attenuated bacteria

Correct Answer: Glycerol or phenol-containing buffers

Q16. Compared to subcutaneous immunotherapy (SCIT), sublingual immunotherapy (SLIT) typically offers which advantage?

• Higher systemic anaphylaxis risk
• Improved home administration and better safety profile
• Requires hospital infusion only
• Contains live allergens for potency

Correct Answer: Improved home administration and better safety profile

Q17. A key immunological mechanism of successful allergen immunotherapy is:

• Permanent deletion of IgE genes
• Induction of blocking IgG4 antibodies and regulatory T cells
• Increasing mast cell numbers
• Enhancing Th1 to Th17 shift

Correct Answer: Induction of blocking IgG4 antibodies and regulatory T cells

Q18. Which clinical condition is a relative contraindication to initiating allergen immunotherapy?

• Well-controlled seasonal allergic rhinitis
• Uncontrolled severe asthma
• Mild intermittent eczema
• Allergy to seasonal pollen only

Correct Answer: Uncontrolled severe asthma

Q19. First-line emergency treatment for systemic anaphylaxis due to natural allergens is:

• Oral antihistamine and observation
• Intramuscular epinephrine immediately
• IV antibiotics
• Topical corticosteroid application

Correct Answer: Intramuscular epinephrine immediately

Q20. Which characteristic of an allergen protein increases likelihood of causing severe food allergy reactions?

• High heat-lability and rapid digestion
• Heat stability and resistance to gastrointestinal digestion
• Exclusive presence in fermented foods
• Low molecular weight below 2 kDa only

Correct Answer: Heat stability and resistance to gastrointestinal digestion

Q21. Alternaria and Aspergillus are natural allergens primarily classified as:

• Bacterial endotoxins
• Fungal/mold allergens associated with respiratory disease
• Viral proteins causing hypersensitivity
• Synthetic chemical sensitizers

Correct Answer: Fungal/mold allergens associated with respiratory disease

Q22. Natural rubber latex allergy is primarily due to proteins from which plant?

• Hevea brasiliensis
• Gossypium hirsutum (cotton)
• Glycine max (soy)
• Oryza sativa (rice)

Correct Answer: Hevea brasiliensis

Q23. Aqueous versus glycerinated allergen extracts differ mainly in:

• Route of administration only
• Preservative content and shelf-life stability
• Ability to generate IgG exclusively
• Their origin from synthetic peptides only

Correct Answer: Preservative content and shelf-life stability

Q24. Which adjuvant is commonly used in experimental allergy vaccines to boost immune response?

• Alum (aluminum salts)
• Mercury thiomersal alone
• Live attenuated virus
• Ampicillin

Correct Answer: Alum (aluminum salts)

Q25. Perennial allergens are best exemplified by which of the following?

• Grass pollen
• Tree pollen
• House dust mite and pet dander
• Seasonal ragweed only

Correct Answer: House dust mite and pet dander

Q26. The ‘hygiene hypothesis’ suggests increased allergy prevalence is linked to:

• Excessive early-life microbial exposure
• Reduced microbial exposure and altered immune development
• High vaccination rates only
• Exclusive consumption of processed foods

Correct Answer: Reduced microbial exposure and altered immune development

Q27. First-generation antihistamines differ from second-generation mainly by:

• Higher selectivity for H2 receptors
• Greater central nervous system penetration causing sedation
• Being specific IgE blockers
• Only available as injectables

Correct Answer: Greater central nervous system penetration causing sedation

Q28. Montelukast, used in allergic disease management, primarily blocks which pathway?

• Histamine H1 receptor
• Leukotriene D4 receptor (CysLT1)
• COX-1 enzyme irreversibly
• IL-5 receptor signaling

Correct Answer: Leukotriene D4 receptor (CysLT1)

Q29. Recombinant allergen molecules and epitope mapping are valuable because they:

• Increase nonspecific IgE binding
• Allow precise diagnosis and design of safer, standardized immunotherapies
• Replace antihistamines in acute therapy
• Eliminate need for clinical history

Correct Answer: Allow precise diagnosis and design of safer, standardized immunotherapies

Q30. An elevated total serum IgE level indicates:

• Specific allergen sensitization without need for testing
• Possible atopy but is nonspecific and requires component testing for confirmation
• Definitive absence of allergic disease
• Only parasitic infection and never allergies

Correct Answer: Possible atopy but is nonspecific and requires component testing for confirmation

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