Correct option is C
Explanation-
Background on B-cell development (from stem cell to mature B cell):
1. Pro-B cell:
(i) CD45⁺, CD43⁺
(ii) Germline or DJ rearranged heavy chain
(iii) No surface IgM
2. Pre-B cell (large & small stages):
(i) CD45⁺, CD43⁻ (CD43 gets downregulated as cells progress)
(ii) VDJ rearranged (μ chain made)
(iii) No IgD yet
(iv) Surface or cytoplasmic μ (IgM⁻ or IgMlow)
3. Immature B cell:
(i) CD45⁺, CD43⁻
(ii) Expresses IgM⁺ but not IgD
4. Mature B cell:
(i) CD45⁺, CD43⁻
(ii) Expresses both IgM and IgD (IgMhi, IgDhi)
Analysis of Each Row:
Correct Inference
A: CD45R⁺, CD43⁻, mIgMhi, mIgDhi → VHDJH–Cμ → Mature B cell
Fully rearranged Ig heavy chain and expression of both surface IgM and IgD.
C: CD45R⁺, CD43⁻, mIgMlow, mIgD⁻ → VHDJH–Cμ → Late pre-B cell
Low surface IgM suggests small pre-B stage transitioning to immature.
CD43 has been lost → post-pro-B.
E: CD45R⁺, CD43⁺, mIgM⁻, mIgD⁻ → Germline configuration → May not be B-cell precursor
No rearrangement, no surface Ig → could be non-B lineage. Early progenitor or irrelevant cell type.
Incorrect Inference
B: CD45R⁺, CD43⁺, mIgM⁻, mIgD⁻ → Germline → Pro B cell
This would be true if DJH rearrangement had occurred. But “germline” suggests no rearrangement at all, which is before pro-B. So calling it pro-B is premature.
D: CD45R⁺, CD43⁻, mIgM⁻, mIgD⁻ → VHDJH → Immature B cell
Immature B cells must express surface IgM. But mIgM is negative.
VHDJH rearrangement suggests a pre-B cell that hasn’t expressed μ protein yet.
Final Answer: Option c – A, C and E only are correct.
