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#RPMI-1640

2 public questions tagged with this topic.

Animal Tissue Culture 1

The optimal CO₂ level for RPMI-1640 is:

RPMI-1640 medium composition explicitly optimized for 5 percent carbon dioxide environment commonly found in mammalian cell incubators set to human alveolar condition. Formulation contains sodium bicarbonate 2000 milligrams per liter equivalent 23.8 millimolar. Applying Henderson-Hasselbalch equation with pKa 6.1 target pH 7.4 requires ratio bicarbonate to dissolved CO2 equals antilog (pH-pKa) = antilog 1.3 = twenty to one, implying dissolved CO2 needed about 1.2 millimolar which corresponds to gas phase about five percent at sea level 760 mmHg total pressure accounting for water vapor 47 mmHg. At one percent CO2 insufficient carbonic acid forms medium turns alkaline pH above 7.8 reducing transferrin iron uptake because receptor binding requires slightly acidic endosome and impairing interleukin-2 dependent proliferation of T cells due to IL-2R alpha downregulation at alkaline pH. At ten percent CO2 excess carbonic acid acidifies to 6.9 causing mitochondrial depolarization via proton leak, caspase activation, slowed growth. Empirical growth curves of lymphoblastoid lines CEM, Jurkat, Raji show doubling time minimal twenty four hours at exactly five percent.

Ref: Gibco RPMI 1640 protocol 5% CO2 23.8 mM bicarbonate pH 7.4; ATCC RPMI formulation optimal lymphocyte 5% CO2 Henderson-Hasselbalch.

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Animal Tissue Culture 1

RPMI-1640 medium is commonly used for culturing:

RPMI-1640 originally developed by George Moore, Robert Gerner, and Herbert Franklin at Roswell Park Memorial Institute Buffalo New York 1967 for establishment of human lymphoblastoid cell line number 1640 from peripheral blood without fibroblast feeder layer, tailored specifically to suspension hematopoietic cells with distinct requirements versus adherent fibroblasts. Distinguishing features include low calcium 0.42 mM versus 1.8 mM in DMEM reducing cadherin mediated homotypic aggregation causing clumping and death of suspension lymphocytes, high inorganic phosphate 5.6 mM versus 1.0 mM supporting high nucleotide synthesis demand during rapid S phase, reduced bicarbonate 24 mM versus 44 mM compatible with 5 percent CO2 avoiding alkaline drift detrimental to lymphocytes sensitive to pH above 7.7 where interleukin-2 receptor alpha signaling diminished, and enhanced vitamin repertoire including biotin cofactor for acetyl-CoA carboxylase, vitamin B12 for methionine synthase, para-aminobenzoic acid precursor folate supporting rapidly dividing immune cells lacking storage. Glucose modest 2 grams per liter prevents lactate overproduction, glutathione reducing agent plus phenol red indicator present.

Ref: Moore et al JAMA 1967 199:519 RPMI-1640 lymphocyte medium low calcium; Gibco RPMI handbook suspension immunology assays.

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